The Perpetual Bond

When the TARDIS materializes in a familiar junkyard in the 1960s, the Doctor and Steven are soon embroiled in a mystery in the City of London. Who are the mysterious bowler-hatted businessmen with their deadly umbrellas? And what secret is young Oliver Harper desperately trying to conceal?

Contracts have been signed. A deal is in place. And the Doctor discovers that perhaps not even he can stop a terrible business...