I don't think there's any getting around it anymore. Gregory Mcdonald's powers definitely waned as his career continued.
Flynn's In is the second novel to star Mcdonald's other recurring character, Boston Inspector Francis X. Flynn, and while the character and his family and his interactions with his short-tempered, unhappy Sergeant "Grover" Whelan are as amusing as ever, this time the plot isn't very fun at all. It's only when Flynn is distracted, by telephone, to deal with his regular players that things really spark. The supporting cast this time out really requires some work.
In this novel, Flynn is summoned out of state on a secret assignment by the police commissioner. He arrives at an exclusive, hidden resort for the rich and powerful, called simply The Rod and Hunt Club, where one of the members has apparently killed himself in a shooting accident. Flynn quickly determines that he was killed elsewhere and his body moved. The club has decided to cover up a murder, and they've got the full support of the police in this isolated community. Flynn has merely been called in so the members can mete out their own justice. It won't come as any surprise to learn that somebody's got their own ideas of justice for the club.
The problems are just huge with this one. In an unhappy echo of Fletch's Moxie, Mcdonald has populated a cast of eccentric, unpleasant idiots who mostly speak with a single voice. Beyond "the old nudist" and "the cross-dressing judge," I couldn't tell any of these jerks apart. Mcdonald also made the remarkably bad choice of making Flynn by far the most intelligent and witty member of his cast. It really just becomes tedious and aggravating to continue. As the body count grows, it's impossible to tell whether Mcdonald is parodying a plot that was boring when Christie ran it into the ground, or if he's just plain lazy. Funny in places, particularly where Flynn's children are concerned, but a drag otherwise. Not recommended.