"Riddle Me That, Part 1 of 5"
*The Riddler is back. He has kidnapped Doctor Brendan Dallaway, and Batman senses that he is more dangerous than he used to be. He is intent on tracking the Riddler down, but he also has to contend with Metropolis reporter Kara Harris, who city hall insists should be allowed to do a story on him. He ignores her and heads for the person indicated in the Riddler's clue - a businessman, who has a fake painting above his fireplace, a painting which contains another clue. However, Batman also catches a faint whiff of a particular chemical, and so can trace the Riddler's base - unfortunately, when the reporter catches up with the businessman, he can only tell her about the subject of the clue, not the chemicals.
We also discover how, some months ago, Edward 'Riddler' Nashton/Nigma was living rough, but was discovered by Professor Jarrod Buttery, who noticed his gift for crosswords. Buttery decided to take Edward into his home. *Source: DCUGuide.com