Zeus was an omniscient and omnipotent god who ruled in Heaven where the gods lived. However, he was a pervert who had a wish to flirt with young angels, unbeknownst to his wife, Hera.

He came up with an idea to make use of the promotion examination which took place every three years. Three angels, Yu, Miki, and Chado-ko, came down to Earth to take the exams. When they began to work part-time jobs at the flower shop, the severe trials occurred one after another.

Zeus was taking care of them secretly. However, it's wasn't from his kindness, but from his perverted desires. But, his activities were known in the lower world...

[From AniDB]