The Box (1) - S11.E7

D.C.S. Walker goes on leave back to Glasgow, where he is taking care of his increasingly senile mother, he soon becomes involved in the case of a missing woman, who is the sister of an old friend. Walker begins to delve into the life of her then husband Kevin Reid, and discovers a dark bond between him and his brother Ronnie. Soon a body is discovered and is it is proved to be the missing woman. Then Kevin's second wife is reported missing - convincing Walker that one or both of the Reid brothers are involved in the crimes.