The Thief - S2.E4

Resident Betty claims that her sewing basket has gone missing and Tom and Diana decide to investigate. Not fully believing Betty's story they follow her and Tom intervenes when they see her apparently shop-lifting. Tom is arrested and conducts his own court case, being found not guilty of theft, but guilty of contempt of court.

Later, Diana recalls that she had the sewing basket all along, having borrowed it from Betty and forgetting she still had it.