Ryuji Kisaragi is a normal high school boy living a peaceful life, which is turned into an adventure when his second cousin Eriko suddenly returns from overseas. He gets recruited into her organisation, the Seven Tails, in order to help her find artefacts called Lost Precious. Ryuuji and Eriko manage to seize a relic box from a black broker named Fang. Inside the box they find a girl whom Ryuuji names Rose because of the rose like pattern on her left hand. When it turns out that Rose is in fact a Red Dragon, Ryuuji decides to protect her from the black organisation using his powers as a level 10 Breaker.

Because his friends fired a rocket into the US Army camp, Suzuki was wanted by the US Army and the police. While he was running away the sea surface suddenly rose, and when a brilliant light appeared he saw a strange looking battleship flying in the air. He was dumped into the sea and when he crawled onto the battleship there was a beautiful girl standing there. She said her name was Lyx, the princess of another world, and added, "My Father is Japanese, Shinjiro Sakomizu. Please help me, Suzuki." Based on the novel series by the Gundam creator Yoshiyuki Tomino.