In Murder Goes for a Swim, Michael Lanyard, once a notorious thief known as the Lone Wolf, finds himself at a charity event hosted by the wealthy Rutherford Bonds. The evening begins with a mysterious phone call from a woman named Betty Lawson, who urgently implores Lanyard to attend the gathering, hinting at an impending murder. Intrigued and concerned, Lanyard and his loyal companion, Jameson, arrive at the opulent estate, where they are greeted by a colorful array of guests, including the glamorous beauty Cynthia Waring and the infamous gossip columnist Ralph Clinton.