 The TARDIS arrives on-board the passenger space vessel "Empress" which has collided with the survey ship "Hecate" in hyperspace. The Doctor, Romana and K-9 offers to help separate the two ships which are causing unstable anti-matter barriers on-board. Where the Doctor meets a eccentric scientist named Tryst who have invented a machine that can project living images of planets via laser crystals. Only to learn Mandrels, monstrous alien creatures from the dark and dangerous jungle planet Eden have escaped from the machine and The Doctor, Romana and K-9 suspects drug smugglers are smuggling a dangerous narcotic called "Vraxoin" on-board.