In the future, a team of scientists have discovered a wormhole at the edge of the solar system and a new planet. The lead scientist names it Remina, after his only daughter. Once it is discovered that Remina is not a planet, but a world eating entity, the people of Earth panic as they go at great lengths to kill the girl who named the planet in hopes it will save their world.
The story begins with Remina and an unknown man tied to crosses as people around her pray for her death as a ominous eye looks down from the sky. Skipping back one year, the story tells of how colonies have been established on the Moon and Mars as Professor Oguro discovers a wormhole at the edge of the solar system where a planet can be seen in the area of it. He names it Remina, after his only daughter, as the world becomes mopped up in a frenzy to push the girl as a pop icon. After much deliberation, Remina agrees to be a Japanese idol as her popularity spreads all across the world. Meanwhile, the astronomers notice that stars and planets that are around planet Remina disappear for some reason but dismiss it as nothing. Gaining sponsorship from Gensaburo Mineishi, she is invited to dinner with her manager Yasumi Mitsumara. She is later given a tour of the mansion by Genasburo's son, Kunhiro, as she tells him how his missing older brother wanted to become an astronaut and how his family has a fallout shelter.
Soon after, the team of scientists find out that Remina has stopped dead and is heading for Earth. One scientist goes mad, stating that he met eye contact with Remina and that it has become aware of Earth's existence as well as it'll be at Earth within a month. The news gets wind of it as people are told not to panic. People do just that as Remina is attacked at her birthday party as new images come from Saturn as Remina collides with it as the planet disappears. The masses are convinced that because the planet was named after a girl, if the girl were to die, so would the planet.
At the astronomy lab, the scientist discover something disturbing: anything that comes into contact with Remina disappears around it as evident by Jupiter being sucked into it. A satellite image shows a large, tongue like protrusion coming out of Remina, wrapping around Mars, and swallowing it whole. They realize that Remina is not a planet, it is a planet eating entity. As news comes in about Mars, the masses riot, looking for Remina as Yasumi, Kunhiro, Goda, the president of her fan club, and the vice president of the fan club rescue her. Fleeing, they see the public erecting two crucifixes as they see in the sky the planet Remina descending upon them.
As the people watch Remina from the sky, the news reports that a spaceship from the Moon is going to investigate Remina. As the astronauts orbit Remina, they see a massive white canyon with a black center. Trying to pass it off as some volcanic area, they soon realize that the object is a giant eye, trailing their ship as it roams around it. Remina and her friends wonder what is going on as they watch television, seeing that riots have occured all across the planet as a group of masked men interrupt the broadcast. They state that Oguro and Remina are to blame for what is happening and the only thing to do is kill them. The men argue about it as they fight until Yasumi breaks it up. Hearing a commotion, the mob has trailed them to the apartment as they bang the door. The fan club vice president tries to escape but is gunned down. Fighting off the mob, they are able to escape down a trash chute.
At the lab, Oguro and his men are discussing with world leaders about how to save the planet. Oguro has nothing until a message comes from the probe that was sent to investigate Remina. Getting a feed, they see bizarre alien life on the planet's surface as the astronauts suggest sustainability is possible but hazardous as they spot sapient beings in the fog before the feed is cut. Oguro wonders what to do as his assistant informs him he shouldn't leave as mobs of people are outside the building, wanting his blood.
Remina and company are able to sneak through the sewers to escape but the mob encounters them once more. Running into an alley, Kunhiro saves himself as the president and Yasumi defend her. The mob grabs the president as they try to kill Remina, Yasumi taking the blows as he is killed, apologizing to her for not being able to protect her fully. The mob comes down on her but the cultists announce that her death must be done on a sacred altar. Goda scorns Kunhiro as he tells her he'll get her out as Remina sees that the mob has captured her father. Oguro apologizes for befalling this on her as he is stabbed and killed by the masses.
Remina mourns her father's murder as she is ordered to be tied to the other cross for a sacrifice. Goda tries to do something but everyone stops as the clouds part, Remina looking down on the planet. Eyeing the moon, it unleashes its tongue and swallows the moon whole. Panicking, the tongue descends upon the planet as hundreds of missiles are shot at it. However, they deflect and fall back to Earth as people flee as the cities are destroyed. Goda seizes the opportunity to rescue the unconscious Remina as he tries to comfort her through Yasumi and her father's death. As he tells her how much he admired her, they stumble across Kunhiro. He tries to downplay what happened earlier as he and Goda fight. Remina chastises them saying she hates fighting as Goda leaves dejectedly. Kunhiro feels he has a golden opportunity as he rescues Remina back to his mansion.
Kunhiro's parents that he brought Remina with them as they state that their association with Remina has cost them lots of money. Kunhiro tries to plead his case but his father announces that they are going to seek refuge on the surface of Remina itself as they got news of the feed as well as he is convinced that one of the astronauts is his missing son who is using a pseudonym. Kunhiro is happy to hear it but wants to bring Remina with them. His parents again call her a harbinger of destruction as Kunhiro states that he will marry Remina as he drags her down to the fallout shelter.
Remina states that while she is thankful, she wants to remain on Earth as she has nothing to live for anymore. Kunhiro rebuffs this, making advances on her as he feels she should be grateful for saving her life. He makes advances on her, pushing her to the ground in an attempt to rape her. She defends herself long enough for Kunhiro's parents to come by, Kunhiro claiming Remina made advances on him. His mother beats Remina to a pulp as the parents toss her to the mob. The cultist leader states that while they need to kill her, the hunt makes it more fun as he whips her, having the mob chase her around. Before any of them can get far, the wind picks up in a massive storm.
The mob is rattled by the wind storm and subsequent earthquake as they are unsure what all is going on with Planet Remina. Someone points out that since the Earth is orbiting a mass much bigger than it, its crust is suffering extensive damage as they continue to hunt Remina. Crawling into a makeshift hut, a bum stumbles across Remina who begs him to let her hide from the mob. They find her anyway as they capture the bum as well, the cultist leader deciding to torture them first by stringing them on trees and whipping them, drowning them, and then dragging them back to the court yard as they can see Planet Remina's tongue through the atmosphere. The cultist shows Remina that her father's corpse burned up in the missile strike as they tie the bum and Remina to the same cross over the Oguro's body.
Deciding now is the time, the mob lights a pyre to burn the two, trying to make quick work of it as Planet Remina's tongue penetrates the atmosphere as it touches down on the planet's surface. Due to this interference, the mob disperses in the chaos as the cultist latches on to Remina, licking her face in a grotesque manner. The bum tries to awaken Remina from the shock as he looks in the distance as he sees that a massive tsunami is heading their way. Submerged underwater and still tied to the cross, a rocket jettisons into space as the Mineishi's have gathered key figures from Japan and launched them into space to Remina. However, only those who are deemed worthy were allowed to leave Earth to the alien world.
Back on Earth, the tsunami's waters have subsided as the bum pants for breath. Remina is still unconscious as the bum attempts to awaken her. Instead, he sees that the sky is spinning. Wondering what is going on, he sees that the whole world is spinning like a massive top.
The bum realizes that the planet was licked and as a result, the whole world is spinning rapidly. As Remina wakes up, the bum tries to untie them as the cultist emerges from a building to snatch Remina. Leaping high to a building, he slams Remina into a building as the bum realizes that because of the spinning, the Earth's gravity is low and that he can use centrifugal force to leap around like the cultist. Rescuing Remina from the man, the cultist alerts all survivors of Remina's location as they spring together, using the forces of gravity, to pursue Remina and the bum. As they float above the surface, the bum is surprised by a gigantic fault made by Remina's tongue. Feeling the wind give them a push, he wonders how much longer they can keep this up.
Up in space, the rocket ship is preparing its descent onto Remina's surface. Trying to ensure a soft landing, they use the rest of their fuel to get to safety on the planet, following the electrical sources from the first spaceship. However, the surface is much more dense than any of them predicted as they crash on the surface. With some injured, Kunhiro notes the odd wildlife on the surface as the prime minister and Gensaburo wonder what the next step of action it, curious if this planet is truly sustainable. They come up with a plan: take a critically injured passenger, take off their helmet, and see if the atmosphere is safe. They do this but discover the atmosphere to be corrosive as the man melts into a pile of waste, alerting the passengers on Remina.
As Remina awakens, she wonders what's going on as the bum explains how they are flying over Africa and that the entire population of the world is after them now. Seeing the thousands of people chasing them, the bum announces that he will do what he can in order to ensure her safety.
As people from all over the world chase the two, the bum jokingly asks what it feels like for the whole world to want her dead. Remina asks for her to be let go as the bum knows that her death would not fix anything as he dodges several attacks from survivors. However, things get too much as they make a stronger advance. The bum sees Japan in the distance, feeling the air in the atmosphere is thinning out as Mount Fuji has erupted. The masses come upon Remina as the whole force of humanity comes to a dead stop in the middle of Tokyo as the Planet Remina watches from the skies. On its surface, the survivors are concerned as the atmosphere melts people and they only have two days of oxygen left. Unsure of where to go, they notice how the melted man's face has been absorbed by the planet as a tongue comes out, killing several survivors.
Kunhiro and his family flee in terror as they come across the the astronaut they suspect is his brother. Instead, it is a hollow space suit of the deceased astronaut as the wild tongues of the planet's surface comes down upon them, their screams echoing in the atmosphere. In the pile of dead bodies, the bum and Remina emerge as Planet Remina wraps its tongue around Earth. Fleeing, the bum is crushed by a building as he is able to lift it up; point out that the low gravity is making everything lighter. They come across a family huddled in some ruins as the bum brings them with him as well. Remina wonders where they are being taken as he leads them to the Mineishi mansion as its still in tact. Leaping over the fence, the low gravity nearly sucks them all up into the atmosphere as the bum is able to pull down on the door. The cultist grabs Remina, trying to attack as his mask is lifted, revealed to be Goda as he was jealous before he is sucked up into the atmosphere.
As Remina begins to devour the planet, the bum brings the group to the basement as Remina sinks its teeth into the surface, eating Earth whole. As Planet Remina leaves the area of what was once Earth, Remina wonders what just happened. The bum states they are in the fortified fallout shelter from the Mineishi's basement as the series of explosions rocked the shelter into space and have a year's worth of supplies given the number of people. Remina figures out that the only way the bum would have known about the shelter was if he is the missing son of Gensaburo: Daisuke. He confirms this as the couple thank them as they express joy in seeing Remina, big fans of hers. They also point that the children with them were survivors they found. They wonder what their next step will be as Daisuke puts it bluntly: pray for a miracle within the year. As they float in space, Remina looks at the empty void as she expresses her sorrow for the loss of Yasumi and her father.