Everyone knows about the four gorgeous guys who work at "The House of Kittens" flower shop. But what they don't know is that it's just a cover. Omi, Ken, Aya, and Youji are all assassins working for Persia to kill all the bad people in the world. Each has their own secrets and pasts that hurt and connect them to each other as they team up to "deny these dark beasts their tomorrows".