A new communications system causes problems at Cresta Cabs. Sam and Reen accidentally broadcast a private conversation to all cabs. Sam's partner Dexter returns from abroad after a breakdown caused by his unfaithful wife Tina.

Cresta Cabs is short of drivers, but Dexter has not returned to work yet. He wrongly suspects Tina of being unfaithful again and gets Cambridge to destroy an expensive painting he bought her, not realizing that Cambridge is in someone else's house.

Dexter sees the insurance salesman Tina had an affair with at his house. He jumps into the Thames, and soon afterwards the insurance salesman's body is found in the boot of one of the mini-cabs.