The Unicorn Curse. Lowan, #13

Meet Lowan, a telepathic alien working as a private detective in the 1930s!The Bearance, a rusty costal freighter, sank in a storm a month ago. Now, a killer codenamed Poseidon is murdering the remaining members of the crew-viciously, with a harpoon-and he's looking for Teddy Bear. Why? The killer wants the unicorn staff, an antique ivory and gold artifact worth as much as a million dollars, which he plans to sell at a high-stakes auction aboard his luxury yacht.
Lowan, desperately in need of a few days off, is resistant to investigating. But when he learns what's at stake, he procures an invitation and joins the auction in disguise. He finds himself trapped aboard the killer's yacht, and each of the five other auction attendees will stop at nothing to win. S. E. Grosskopf's writing is strongly influenced by the old pulp fiction magazines and Golden Age radio dramas of the 1930s-1950s.
If you like fast-paced action and mystery with a dash of urban fantasy and quirkiness, then you'll love these books. This is the thirteenth book in the series. The books follow chronologically. Reading them in order is recommended.