L@ve Once (read as "love at once") is a romance visual novel that tells the story of a boy called Shouji Takanashi (高梨 翔司) whose mother is a mermaid. He met mermaids as a small child but forgot about them. One day, his father passes away and not long after, two sisters, who happen to be mermaids as well, come to his place. Their names are Mei and Meru. Being a son of a mermaid, he can only fall in love once, as broken heart would be the end of him. With the help of Mei and Meru, he will hopefully be able to find his true love.

The game originated on PSP and is a light visual novel without any adult content. A year later the game was ported to PS3 with some changes and additional content under the title L@ve Once: Mermaid's Tears. Both platforms have limited edition releases which feature bonus content such as audio drama, artbook or soundtrack.