Philip Marlowe's on a case: his client, a dried-up husk of a woman, wants him to recover a rare gold coin called a Brasher Doubloon, missing from her late husband's collection. That's the simple part. It becomes more complicated when Marlowe finds that everyone who handles the coin suffers a run of very bad luck: they always end up dead. That's also unlucky for a private investigator, because leaving a trail of corpses around LA gets cops' noses out of joint. If Marlowe doesn't wrap this one up fast, he's going to end up in jail or worse, in a box in the ground.
