Eight- and nine-year-olds joe and Frank Hardy are on the case! Frank and Joe are brothers, but that won't stop them from competing against each other at the Fun World arcade's video game tournament. The boys make a bet: Whoever wins the competition gets to move into the cool new room their dad just built! But suddenly money goes missing. The owner of Fun World shuts down the tournament until the stolen cash is returned! Can the boys figure out who took it? Or will their chances of victory -- and a brand-new room! -- be crushed by a thief?