Under the Skeleton Flag — Russell James

It is 1718 and Doctor Baxter Whitcomb decides to leave his medical practice in London for the challenge and adventure of practicing in the Massachusetts Bay Colony. But while crossing the ocean, his ship is boarded by pirates. And not just any pirates, these are commanded by the notorious Blackbeard, sailing under his trademark skeleton flag. Blackbeard kidnaps Baxter and presses him into service aboard his flagship. Baxter soon discovers the secret to Blackbeard's success. A powerful witch is aboard, casting spells of dark magic that make the pirate invincible. The doctor's voyage becomes a living hell. Storms, battles, the mercurial whims of Blackbeard, and the witch's spells constantly threaten his life. He second guesses every action he takes, every word he speaks. Then the witch falls ill, and Blackbeard commands the doctor save her. But can he treat an illness brought on by her practicing the dark arts? If he can't, Blackbeard has promised the witch won't be the only one to die while sailing under the skeleton flag.