During Rose's first moments inside the TARDIS,the doctor offers to take her anywhere in time she wishes to go. The pair wind up at her continual need to travel forward in time billions of years into the future onto Platform One,an observation facility where the galaxies most elite have come to watch the planet Earth,being held in place for millennia be swallowed up by it's sun as nature intended. Many of the guests are aliens descended from lifeforms on Earth,including a tree-like humanoid named Jade whose scan of the doctor reveals his true identity to her. The host of the event is the Lady Cassandra,the last pure blooded human who is now,after many surgeries, little more than a flattened Hyde with a face. Something is amiss as members of a people called the Repeated Mean have offered the guests a gift,who turn out to be robotic spiders who have become intent on sabotaging the platforms sun filter as the Earth is enveloped by it's sun.
As Rose attempts to cope with her surroundings and her puzzlement at the doctors ambiguous identity,she soon finds herself to be a near victim of the sun filters malfunction. After investigating the sabotage with Jade the doctor comes to the conclusion the spider robots are being controlled by one of the observers on the platform. It is not the Repeated Mean as suspected,since they too turn out to be androids. It is in fact Cassandra,who is trying to destroy the platform in order to avoid paying for the financial expenditures of the surgery she has had to keep herself alive. At the willing sacrifice of Jade's life,the doctor is about to re-activate the sun filter from the source. He saves the life of the observers and Rose,however Cassandra finally implodes to death due to lack of moisture. Upon leaving the doctor returns Rose to her time,where he explains he is the last of the dead race of time lords and offers for her to remain on Earth. She decides to travel with him instead.
A fascinating example of future fiction,this story makes excellent use of the relaunched Doctor Who's superior CGI visualizations-with the stunning depiction of the Earth's absorption by the sun and the different aliens within Platform One. More important to it's success is the story line itself. The main thrust is Cassandra,literally a frail shell of a human whose bad attitude outweighs her weak physical state,is completely insipid to Rose. Even when the doctor is forced to destroy her,it is completely justified,as he says,because all things must eventually end. The story asks many psychologically intense questions about the importance of life and the necessity of death. There is a great deal of humor interjected too-from Rose's comparison of Cassandra to Michael Jackson to the notion of contemporary pop music,such as Britney Spears "Toxic" as being one day thought of as classical music. Overall this is one of the modern Doctor Who's greatest epic stories.