Author's website (https://stevehiggsbooks.com/patricia-fisher/) lists this title as the first in the Patricia Fisher Cruise Mysteries.

How do I always attract trouble and drama? When a crewmember takes his own life but hands Patricia a cryptic note and a request to save Anna just before he jumps, she feels she has no choice but to honour his dying wish - save Anna ... ... who is Anna? The note leads her to investigate the odd-looking and mysterious couple staying in cabin 2124 and so begins an adventure that leads Patricia and her friends through the streets and underbelly of Tokyo, Japan. Why did he kill himself? And what are the couple in 2124 up to? The quest to save the unidentified Anna is not her only problem, though. The captain, who has always been warm and friendly, appears to now be flirting with her. She's in her fifties, for goodness sake! How can she be thinking about starting again, but goodness, he is handsome and oh so charming. Before she can get to grips with that, they dock in Japan where waiting for her at the port is none other than her estranged husband, Charlie, the man whose cheating behaviour acted as the catalyst for her around the world adventure. He isn't done with their marriage it seems, but how does Patricia feel about him now that her anger has had time to dissipate? A mystery to solve, two men to pick from; how did her life get so complicated? Join Patricia and gang again for another pulse-pounding adventure onboard the world's finest luxury cruise ship.