The Doctor takes Rose Tyler on her first trip in the Tardis to the end of the world, roughly five billion years from now. It is hours before the Sun grows into a red supergiant and consumes the world.
Visitors from around the universe have gathered together on a space station called 'Platform One' to witness the event. Those invited include the representatives from the Forest of Cheam, humanoid life forms that are effective humanoid trees. Also invited is the Face of Boe, a creature that is just a giant head in a large glass container. There are some similarities between this creature and a creature that has appeared in the sci-fi epic, Dune.
The last pure human from Earth, Lady Cassandra is also present. Lady Cassandra is effectively just a sheet of skin that has been stretched with a face in the middle. Cassandra is played for laughs by Zoe Wanamaker.
Whilst those on board await the destruction of the Earth, the platform is being sabotaged by mechanical spiders. First to go is the Steward, the man in charge of the platform. The Steward is a tall deep blue man wearing a cap on his head. The Steward is killed by solar protection being turned off therefore resulting in his death and the solar energy is gradually lowered onto him.
Rose is captured and put in room where the protection from solar radiation is being reduced. The Doctor tries to but can't break into the room. In the end, he goes off to turn on the shields to protect the station from the immense radiation that will be coming their way when the sun turns into a red giant star.
When the Doctor starts to investigates, he comes across a spider and takes it back to the observation lounge. The Doctor turns on the machine which heads to Cassandra. Cassandra had hoped to sabotage the platform so that she could claim on the insurance for all the people on the station. Cassandra teleports off the station to get away from being arrested.
With Jade, the leader of the Forest of Cheam, the Doctor runs off to turn back on the space station protection field. The shield switch is at the far end of the ventilation chamber which has large fans spinning meaning that the Doctor can't just walk across. As the fans spin, the Doctor has to time it right otherwise he'll be shredded. Sadly for Jade, the temperature in the room is too much and she burns up before the Doctor can get to the switch.
The Doctor manages to recall Cassandra so that she can face justice for crimes. Cassandra requires moisturising all the time and when it doesn't happen after being recalled, her skin breaks up and she dies.
The Doctor takes Rose back to the present day so show that everyone is ok. The Doctor suggests they go back in time now to the 19th century.