It is a bomb. That's the point. we're not very sure how much damage the Daleks have done. WELLS: (Quietly.) I need to get back to London. CARL TYLER: The Doctor...where is he? In the sewers of London? BARBARA: It's alright Jenny, it's clear. IAN and LARRY run up next to the machine, passing the creature in the dark.)
Plan: A: The TARDIS; Q: What returns to London in the 22nd century? A: bodies; Q: What is in the river in the 22nd century? A: the docklands; Q: Where is London quiet in the 22nd century? A: The Daleks; Q: Who has invaded London? A: the Doctor; Q: Who is responsible for stopping the Daleks? Summary: The TARDIS returns to London; however, it's the 22nd century. With bodies in the river, and quiet in the docklands, the city is a very different place. The Daleks have invaded and it's up to the Doctor to thwart them once again.