Granny on Board - Secret Agent Granny, #7

I'm Barbara Gold. Age: 70. Height: 5'5". Eyes: blue. Hair: gray. Weight: none of your business. Specialties: Undercover surveillance, small arms, chemical weapons, Middle Eastern and Latin American politics. Current status: Retired widow and grandmother. Octavian takes Barbara on a seniors' cruise for her seventy-first birthday, but the vacation is not all piña coladas and shuffleboard. Barbara makes a frenemy in Georgina Branch, queen bee to a group of equally conniving girlfriends.
Barbara is sure one or all of them killed the passenger who accidentally fell overboard early in the trip. Barbara and Octavian are stuck on a ship with a murderer, but at least the cruise has plenty of booze. Before their vacation gets cut short by another "accidental" drowning, can Barbara find the killer and keep her boyfriend safe?  Read the hilarious 7th book in the Secret Agent Granny mystery series.