I adored "Despicable Me" and my wife and I could never agree which we liked more--that film or the similarly themed "Mega Mind". We liked them both but she preferred "Mega Mind". Regardless, both films are excellent and entertaining for all ages. Because "Despicable Me" made a huge amount of money, it wasn't surprising that soon after they announced they were making a sequel. And, when the early teaser promos arrived in theaters, they stressed the minions and said nothing about the sort of story the sequel would be. This was, apparently, very prescient--as the film turned out to be exactly that--a film with a vague plot but which was worth seeing just for the antics of the minions. In fact, my wife decided to see "Despicable Me 2" simply because she heard me laughing many times at the minions.
The film picks up pretty much right after the first one. Gru has adopted the three little girls and they, along with the minions and Dr. Lethario, are one big, happy family. However, trouble is brewing. Some super-villain has stolen a top secret formula that transforms nice creatures into killing machines--and a top secret international organization approaches the ex-villain, Gru, to help the locate the formula. They give him a spunky female sidekick and eventually romantic sparks fly. As far as the secret formula and the villain are concerned, this really seemed secondary to the romance and antics of the minions--and this plot seemed to wrap itself up quickly and easily.
As I said, the plot, for what it is, is minimal and seems to be just an excuse to watch the minions as well as the romance. And, for me, this was enough to justify recommending the film. Clearly not as good as the original, but filled with fun nonetheless.