Ryuu wasn't about to lose her. He gave her time to see how bad that life could be, while he grew up and got his own life together. Once he can't wait any more he goes to fins her, to save her from gang life, but he is to late. Megumi is not only gone, but she has been completely erased from the minds of the gang girls.
WHen Ryuu finds out that Megumi has been taken to the planet Adrivar, he will stop at nothing to make sure she isn't the one that got away. Even if that means being abducted by the aliens himself and going to their home planet to get his woman back.