If you're not sure if something's supposed to be funny or not, maybe you're just not in on the joke. I felt like I was not in on the joke for The D Train, an ostensible comedy that gets weirdly leaden at the moments it should be achieving comedic liftoff. There are glimmers of sort-of great performances from Jack Black and James Marsden, but the script, written by codirectors Andrew Mogel and Jarrad Paul, ultimately lets everybody down.
Black plays the self-appointed committee chair for the 20-year reunion of his high school class—a position that, in one of the movie's better jokes, simply means he has the password to the reunion's Facebook page. Marsden's a pseudo-successful Hollywood actor who might be the key to getting everyone else to attend the reunion—if only Black can convince him to come.
Movie/sitcom rules require that, in order to pull off this tiny victory, Black has to lie to everybody around him, including his father-figure boss (Jeffrey Tambor) and his loving, supportive wife (Kathryn Hahn). Meanwhile, the filmmakers seem mixed up on chronology: This is supposed to be the class of 1994, but the soundtrack is inexplicably heavy on '80s hits from Mr. Mister, Quarterflash, and OMD. (Where's Tom Cochrane, guys?)
There's a plot twist midway through The D Train that's part of a better, smarter, more self-aware movie. I probably wouldn't be the first to spoil it, but whatever small amount of enjoyment you can wring from the movie will be reliant on what little you know of the twist ahead of time. I will say that this plot point is likely what the filmmakers used to ensnare the talents of people like Black, Hahn, and Tambor. But it's so out of left field, and the behavior the characters demonstrate as a result of it is so bafflingly incomprehensible, that it squanders all the goodwill it could have earned.
Unless I'm simply not in on the joke.