Tom Braudy is enjoying a quiet afternoon when the TARDIS lands in his Nan's living room and interrupts her in the middle of the snooker. After they've apologised, the Doctor and his friends soon discover matters of far greater concern. The street which Tom happily cycles up and down appears to have no beginning or end, and every single house on it is identical. Is this the future of suburbia, or something even more sinister? Why doesn't Tom look as young as he behaves? And can anybody remember which house the TARDIS is in?