Project a Ko 2: plot of the daitokuji financial group (1987)

Three weeks have gone by since the alien spaceship crash landed on the Graviton City spire, and since then the aliens have been hard at work converting their ship to a pleasure district, hoping to make friends with the humans!… Not. Perpetually late and continually over-eating A-ko, spacy and cheerful C-ko, and brilliant and bold B-ko are about to enter summer break from school, and it just so happens the alien ship is open for business. When a free meal turns into a sob story about how the aliens just want to go home, will it be A-ko or B-ko who can get the ship into orbit again?