“Undercover Grandpa” (** out of four) was a contrived comedy about a high-school kid (Dylan Everett) whose girlfriend (Greta Onieogou) suddenly goes missing. Fortunately for him, his grandpa (James Caan) who he is looking after for the evening turns out to be a former C.I.A. badass who enlists his old WWII cronies (Paul Sorvino, Louis Gossett Jr, Kenneth Welsh) for help in tracking her down and kicking one last round of ass. Caan is good in a tailor-made role and it’s nice to see him and the other elderly boys having fun but this dumb and diluted movie doesn’t know what to do with them. Had they waited another few years, this could have been called “The Expendables 4”.