The owner of a seafood restaurant falls in love at first sight...with a merman! Hae-beom, often mistaken for a thug due to his tough appearance, unexpectedly receives help from a mysterious customer named Sang-ah. To his astonishment, Sang-ah turns out to be a merman who requires human saliva in order to gain his legs. Seizing the opportunity, Hae-beom offers him a daily kiss, harboring his own secret hopes and desires. For Sang-ah, it's just a means to an end, but Haebeom can't help but wonder: will Sang-ah ever reciprocate his feelings?