Lord of the Rings: The Two Towers, Mega Man 6, and... do graphic novels count? If yes, Scott Pilgrim... if no, Anansi Boys...
So... Aragorn, Legolas, Gimli, and Megaman must defend Helm's Deep from an army of 10,000 Uruk-Hai, led by Mr. X's robot masters. Meanwhile, Saruman, Mr. X (Dr. Wily in disguise), and the League of Evil Ex-Boyfriends are planning further evil from Isengard when they are attacked by the Ents who are accompanied by Merry, Pippin, and Young Neil. Ramona and Scott Pilgrim use subspace highways to keep up with Gandalf and Shadowfax as the four of them track down Erkenbrand and his warriors to aid Theoden. Stephen Still and Kim Pine tag along with Samwise, Frodo, and Gollum, but are generally inactive and too cool for whatever is going on. Wallace travels with Faramir, and is largely responsible for Faramir's disinterest in the ring, though Wallace sarcastically offers to take it off of Frodo's hands, much to the confusion of Sam and Frodo. Knives Chau and Tamara Chen help Arwen deal with her father and her love for Aragorn. They also dye Arwen's hair. Stacy spends most of this time trying to track down Faramir, only to learn he has been stolen by Wallace.
Or... Aragorn, Legolas, Gimli, and Mega Man must defend Helm's Deep from an army of 10,000 Uruk-Hai, led by Dr. Wily's new robot masters. Meanwhile, Saruman and Dr. Wily are planning further evil from Isengard when they are attacked by the Ents who are accompanied by Merry, Pippin, and Fat Charlie. In the Shire, Spider poses as Samwise Gamgee and seduces Rosie.