Ch. Insp. Derek Conway organises a charity 'lock-up' in the Sun Hill cells - the prisoners for the night being himself, Insp. Monroe, famous boxer Dion Barrie and his manager Max Weir, and Paul Lake, the father of the sick little girl they are raising money for. When Monroe calls in sick, Ch. Supt. Brownlow volunteers to take his place. Sgt. Matt Boyden as custody sergeant must cope with having his superior officers in the cells, as well as a large group of drunken female rugby players. DS Feeney from Barton Street turns up to investigate Barrie for an attempted murder, but Boyden works out that his manager is the man responsible.