Many have wondered whether Robert De Niro has been ruining his esteemed reputation with a string of mediocre films over the past few years, and now Dirty Grandpa provides yet another example in support of that argument. It is a shame to see an acting icon reduced to playing such a sleazy, unfunny and dull character. Dirty Grandpa is about uptight lawyer Jason (Zac Efron) who is forced to drive his widower grandfather Dick (De Niro) to Florida in a bizarre road trip before he marries the bratty Meredith (Julianne Hough). While there are a few good gags, most jokes are repetitive and go too far. Dirty jokes are fine, but there still has to be some substance. Instead, the film totally loses the plot and starts to drag on. Efron's body looks amazing, but he has no opportunity to show his acting abilities. Hough is at least a funny caricature and Aubrey Plaza steals almost every scene she is in, playing the slutty college student trying to sleep with Dick. Ultimately though, Dirty Grandpa tries too hard to be filthy and not enough to be genuinely funny.