The first episode of Welcome to Waikiki introduces three young men who are struggling to achieve their dreams while managing a nearly bankrupt guesthouse called Waikiki. Kang Dong-gu is an aspiring film director whose projects never seem to succeed. Lee Joon-ki dreams of becoming a famous actor, but he can only find small, embarrassing roles that barely pay the bills. Bong Doo-shik is a freelance writer who takes on any job he can find just to help keep the guesthouse running. Despite their hard work, the business is failing due to the lack of guests, unpaid bills, and a series of unfortunate events that leave them questioning whether they should give up on their dreams.
Their lives suddenly take an unexpected turn when they discover a baby left inside one of the guesthouse rooms. Shocked and completely inexperienced in taking care of an infant, the three friends panic as they try to figure out what happened and who the baby's parents are. Their attempts to care for the child lead to a series of hilarious misunderstandings and chaotic situations. From struggling to stop the baby from crying to figuring out how to feed and comfort her, every solution they try only creates more problems. While they argue over what to do next, they slowly begin to develop a sense of responsibility for the little girl.
As the mystery unfolds, Han Yoon-ah, the baby's mother, arrives at the guesthouse. She explains that she never intended to abandon her daughter, Sol, and that the separation happened because of an unfortunate misunderstanding. With nowhere else to live and limited financial resources, Yoon-ah is given the opportunity to stay at the guesthouse together with her daughter. Although the three friends are hesitant at first, they eventually realize that helping her is the right thing to do.