The kids have found out that their monsters will be sacrificed as tribute to some kind of ultimate monster. Their only lead on the case was pulled through a black hole into another plane of existence. Fortunately, the kids stumbled across five bizarre and unique postcards from their recent contact Jack Blackguard alluding to various machinations of the cult.
One of the postcards mentions Sunny Vale, CA, a place apparently hounded by a team of monster fighting superheroes who call themselves the Sentai Rangers. As it happens, Sunny Vale isn’t more than a 3-hour drive from San Frandiago, so after a few “air-tight” alibis and managing to coerce someone with a car to take them there, the kids are off!