Peri hasn't been time-travelling for long and is just getting used to the Doctor and the TARDIS. The Doctor's such a sweet, friendly guy and the TARDIS keeps leaving her little presents, which is neat. When the TARDIS takes them to a party of super-advanced humans on a pleasure-planetoid in the far future (even neater!), Peri falls for the charms of the local hunk and finds herself flying headlong into a quite different form of time-travel...