Robert De Niro goes in all guns blazing as the title character, a foul-mouthed, recently widowed military veteran.

He decides to takes his uptight grandson (Zac Efron) on a recklessly hedonistic road trip to Florida in a bid to loosen him up. So, Efron’s strait-laced corporate lawyer comes in for repeated humiliation from a series of scrapes with frat boys, drug dealers and the police that leave him naked or befuddled or both.

The gags may be mostly witless, but the stars are certainly game. De Niro may appear to be trying to trash his acting legacy with all the crass jokes on offer but he has a ball, as does Aubrey Plaza in the film’s most ridiculously implausible role, a horny college student who has the hots for De Niro.