Steven and the First Doctor, fresh and raw from The Daleks' Master Plan, land in 1966 London. The Doctor thinks this is a kindness after all the death they have recently witnessed, and Steven suggests they go visit Ian and Barbara since the opportunity has presented itself. They split up to try and uncover the aliens' plans: The Doctor to talk to Oliver's boss, and Oliver and Steven to the stock exchange floor to root out the aliens themselves. The plan, predictably, isn't all that benign and the Doctor and companions make efforts to stop it.