Reuniting old friends and introducing new acquaintances, cast members from Heart Signal 2 & 3 are back in a brand new variety series and sparks are sure to fly! Invited to spend a very special winter at Signal House, relationships between Oh Young Joo, Jung Jae Ho, Kim Do Gyun, Kim Jang Mi, Lee Ga Heun, Park Ji Hyun, Seo Min Jae, and Jung Eui Dong are sure to blossom. But which relationships will remain friendly and which will blossom into love? Follow the members through their daily lives and find out! Hosted by Super Junior's Kim Hee Chul and Shindong, Oh My Girl's Seunghee, and Lee Sang Min.