It's Nat's first Valentine's Day with a girlfriend, but unfortunately he has to spend it alone since Rosalina is still away on an around-the-world cruise. But Cooper has other plans for Nat and convinces him to appear on "Pick-A-Teen Date," as one of the teen celebrities attempting to win a Valentine's Day dream date with Victoria Justice. When Rosalina arrives in town for a surprise visit, Nat has some serious explaining to do.
Rosalina finally returns from her round-the-world cruise. But to Nat's dismay, as the band begins rehearsals for a reunion TV special, a rival for her affection shows up. Michel, a handsome young Frenchman from the ship and a brilliant piano prodigy, drives a wedge between Nat and Rosalina which culminates in their breaking up and Roslaina leaving the band. Needing a new bass player, The Naked Brothers Band conduct a nationwide competition and find the perfect choice - except for one problem: Nat isn't ready to let anyone take Rosalina's place.
Finally, The Naked Brothers' major motion picture is ready for release. The studio is hosting a blowout premiere and the question on everybody's mind is who will Nat take as his date? It seems like every girl he's ever met wants to go with him. Perhaps he should look for guidance from Alex who's discovered he has the ability to predict the future with his hair! Bigger problems lurk when a mysterious figure with a grudge against the band vows to ruin the premiere. To top things off, after welcoming a new member into the band (bassist Katrina) Rosalina returns and wants...
The band holds it's annual end-of-the-school-year competition to see who can perform the best prank on his fellow band member and what starts out as innocent fun nearly gets out of hand when Thomas, David, and Qaasim all get arrested! Meanwhile, Nat and Alex discover that girls are harder to prank than boys. And trouble mounts for Alex after his boast that he's the greatest drummer in the world finds its way onto the internet and suddenly the greatest drummers in the world are coming after him.