The title is taken from the name of a Cree Indian, bodyguard to a movie and TV star named Jumbo, who may or may not have killed a young woman (think Fatty Arbuckle). Sixkill is fired when Spenser beats him in a short fistfight and shows up at Spenser's office. He's in sad shape, and it's up to Spenser to show him how to become the man he was meant to be. Hawk is conveniently out of town, so Spenser takes Sixkill to the gym and gets to work. I have a feeling you know how this part of the story turns out.
Meanwhile, Spenser continues to work on the case of the young woman's death in spite of threats from some heavy-duty tough guys. I have a feeling you know how that part of the book turns out, too.
All the elements are familiar. Spenser's actions are predictable. So what? It's like the Nero Wolfe series. If Wolfe didn't count the bottle caps or go to the plant room or wear his yellow 'jammies, I'd be disappointed. Parker makes the familiar fun. The prose is dandy, and the dialogue is as much fun as ever.
There's some talk about death in the book, and the remarks become especially evocative now that Parker's gone. Parker and Spenser had a great run. I'm really going to miss them.