The title of this episode refers to a curious chemical process created by college student Marv Adams (Gary Vinson). Alas, Marv may not only be a drowning duck but a dead duck when he is charged with the murder of unscrupulous private detective Donald Briggs (Harry Landers). Acting as Marv's defense counsel, Perry (Raymond Burr) learns that Briggs was hired by Clyde Waters (Victor Sutherland), the father of Marv's fiancee Helen (Carolyn Craig)--and that Marv's father was Ben Devereaux, who was executed for murder 18 years ago, a fact that Briggs was trying to use to his advantage in extorting money from several other people connected with the case. This episode is based on a 1942 novel by Perry Mason creator Erle Stanley Gardner. ~ Hal Erickson, All Movie Guide