When laidback Greg finds himself at odds with his dad's outsized expectations, pressure builds to turn his act around. After a series of hilarious near disasters, Greg's dad presents him with an ultimatum that just might challenge his wimpy ways for good.

Greg Heffley and his family are getting out of town. With the cold weather setting in and the stress of the Christmas holiday approaching, the Heffley family decides to escape to a tropical island resort for some much-needed rest and relaxation. A few days in paradise should do wonders for Greg and his frazzled family. But the Heffleys soon discover that paradise isn’t everything it’s cracked up to be. Sun-poisoning, stomach troubles and venomous creatures all threaten to ruin the family’s vacation. Can their trip be saved, or will this island getaway end in disaster?