What is the fine-grained topic of the following text: The joys on offer include Fifth Doctor stories The Elite (a twisty tale of the Doctor, Tegan and Nyssa's ill-fated trip to the planet Florana), Hexagora (featuring alien abduction and a proposal for the Doctor) and The Children of Seth (a tantalizing story of the search for the true origins of the mysterious Seth). Only return the topic.
Fifth Doctor stories in Doctor Who series