Thanawat Singsomboon or "Thana" (Kim Jae Wook) and Kunchanita Sasirikorn or "Nita" (Park Min Young) became unmarried parents at a young age even they were still high schoolers. However, due to circumstances happened unexpectedly, Nita raised three sons healthily but grown-up in a romantic relationship between brothers. Even their family life was tested by circumstances, togetherness still unites them despite from thick to thin, and sickness and in health.