Ransom at Sea — Fred W. Hunter

A Chicago senior citizens group boards the stately Genessee for a four-day Lake Michigan cruise. Emily Charters, accompanied by her companion Lynn Francis, senses tension among the dozen or so passengers and crew. But even the sharp-eyed octogenarian is stunned by the brutal murder of Marcella Hemsley only one day after Genessee leaves Navy Pier.

The victim was a nasty sort, but who hated the old girl enough to kill her? When police jail the dead woman's shell-shocked niece Rebecca -- the only member of the group with motive and opportunity -- Emily summons Chicago detective Jeremy Ransom. She clues him in on the strange events that preceded the murder, as well as twists and turns after, then the two piece together a complex tragedy of greed and betrayal, and finger a killer who almost convinces Emily that vacations can be murder.