Cool & Lam are asked to catch an unfaithful husband for a divorce case, but Bertha is greedy. She wants a bigger slice of the cake, which puts Donald Lam in deep trouble, far from the divorce courts and close to dirty cops, blackmail and murder. The Knife Slipped is one their earlier cases in which Donald hasn't developed his strengths and Bertha has to protect the "brainy little runt" from himself.