Mock 2 for 3 (1991)

"For others, Mock is a big thing, but for her is a tiny thing."

Brother and sister invent a new toy model and try to present at commercial company, but fail. Id is a successor of the company, just came back from Japan. He suggests the company should build the new toy with the model that previously rejected. The company cannot find the inventors, so they just manufacture it. Being noticeable, two inventors can recognize and plan to do the revenge.