Out of the Darkness by J. J. Jorgens

Smart Volatile Woman Detective. Check. Suspense. You bet. Interesting supporting characters. Many. Humor. Lots. Settings. Vivid. Writing. You be the judge. What do Russian spies, a vanished filmmaker, a shipwreck, George Washington, Benedict Arnold, and a missing fortune in gold have to do with each other? Mary Jane Morris will find out if it kills her, and it almost does. Badly wounded and suffering from amnesia, grieving for a friend who's gone missing, threatened by Russians who want her dead, it looks like the end for Mary Jane Morris. But she fights back. She retreats to an old house on the Chesapeake Bay where she and teen detective prodigy Jackson tackle the intertwined mysteries of the Russians, a missing diver, a shadowy wreck at the bottom of the Chester River, a trunk full of puzzling letters between George Washington and Benedict Arnold, and a missing fortune in gold. Sometimes the hardest detective work is on cases that happened centuries ago. She vows to find the answers if it kills her, and it almost does.