The game features Frank West, the main character from the first Dead Rising game, and serves as the canon Overtime Mode of Dead Rising 2, with Frank teaming up with Chuck to further investigate the link between Phenotrans and the Fortune City zombie outbreak, and find proof that clears Chuck of any wrongdoing.

The story follows on from Ending A of the main game, with Frank rescuing Chuck from the elevator. Frank was going to meet Rebecca Chang to investigate a Phenotrans facility west of Fortune City, but learns from Chuck that she was killed by Phenotrans mole Sullivan. Although initially suspicious of Chuck because of the media reports blaming him for the Fortune City outbreak, Frank lets the motocross star come with him to find proof that Phenotrans was behind the outbreak.

Case West includes cooperative play for two players, with each taking control of one of the two characters. The episode features new challenges, enemies, items, combo weapons. The photography element returns from the first Dead Rising; the characters use this to generate proof of Phenotrans' part in the zombie outbreaks.