The TARDIS lands in London where the Doctor, Jamie and Zoe agree to help find Isobel Watkins' missing uncle.Searching for Professor Watkins at his last place of work,a multinational electronics supplier, hemeets the company's managing director. He's not what he seems - and possesses alien technology in his office.

The Doctor and Jamie return to the IE factory in search of Zoe and Isobel, where they meet with Professor Watkins and fall foul of Vaughn.