"Riddle Me That, Part 2 of 5"
*Batman finds Riddler and his men, but discovers that Kara Harris has walked into the Riddler's trap elsewhere. He soon realizes that the 'Riddler' who faces him is nothing but a hologram. He is told that a passing train has a bomb on it which will go off in ten minutes - he must prevent this, and must be wearing a particular wristband while he does so. He finds the bomb in the last few seconds of the countdown and looks for a way to get it off the train. Meanwhile, Kara Harris is about to drown in a trap created by the Riddler
Back before the Riddler's transformation, he came to the home of Professor Buttery, who planned to bring out his great genius. He also met Buttery's strong son, Martin. *Source: DCUGuide.com