Miss Happy stars Pancake Khemanit as a happy-go-lucky woman named Happy, who often annoys her best friend Golfie (Ben Chalatit). Unfortunately, Happy is diagnosed with having an irregular heartbeat that will likely cause her death within a month. In an effort to survive, Happy looks up information and finds a YouTube video made by Tul, played by Jitpanu Klomkaew (Ball). Tul's video claims that Happy can stay alive if she dances in the way shown in the video.

Anyamanee傲慢却内心脆弱，以自我为中心。出生在重男轻女的家庭，使她长期压抑。有天遇见了为人正直善良、无私豁达的Guerkhun。Guerkhun准备给予Anyamanee温暖的爱。因为家庭成员包括兄弟Chanuch的去世，两个人的情路并不顺利。同时由于嫂子Pimrata，Guerkhun成为了嫌疑人。Pimrata是一个温柔甜美的女人，在她的生活中拥有完美的东西。她为离开前任嫁给Anyamanee的哥哥Chanuch而后悔，即使为时已晚，她也想和前任复合。