Meet Koh and Yurie. They're a happily married young Japanese couple who moved from Tokyo to San Francisco a year ago due to a job transfer. In early September, while on a business trip back home, Koh bought a new game cartridge for his Nintendo DS. It was mostly out of curiosity -- the Japanese Twitterati were all abuzz over a new dating sim called Love Plus, and he just wanted to see what the hype was about. "I've tried the other dating sims before just for kicks, but I never got hooked," he says. "I didn't expect this to be any different." He was wrong.