Bank robberies should run like clockwork, right? If your name's Parker, you expect nothing less. The Sour Lemon Score finds Parker wrapping up a heist where everything has gone right. But then one of his partners gets too greedy for his own good. The four-way split following a job leaves too small a take for George Uhl, who begins to pick off his fellow heisters, one by one. The first mistake? That he doesn't begin things by putting a bullet in Parker. That means he won't get the chance to make a second. One of the darkest novels in the series, this caper proves the adage that no one crosses Parker and lives.