The pinky swear is an act that may seem childish, but when taken seriously, it can also represent an unwavering vow. At seven and 17 years old, LUO Yang-yang made promises to CHEN An-yu and delivered each time, comforting An-yu’s insecurity caused by his low self-esteem and broken family. Just when their relationship is about to blossom from friends to sweet lovers, an accident suddenly strikes An-yu’s family. As he learns an undesirable truth, An-yu makes the decision to move far away. From the moment they reunite at 27, they both face the choice of either just giving in and going with the flow or following what their hearts initially desired. As a pair of lovers who have already broken up, they each use their own ways to safeguard every “pinky swear” they made to each other in the past, redefining their sweet commitment in love.