Doctor Who: The Death Pit (Time Trips)

Something odd is going on at the Fetch Brothers Golf Spa Hotel. Receptionist Bryony Mailer has noticed a definite tendency towards disappearance amongst the guests. She's tried talking to the manager, she's even tried talking to the owner who lives in one of the best cottages in the grounds, but to no avail. And then a tall, loping remarkably energetic guest (wearing a fetching scarf and floppy hat) appears.
The Fourth Doctor thinks he's in Chicago. He knows he's in 1978. And he also knows that if he doesn't do something very clever very soon, matters will get very, very out of hand.