Wonderful Life

Confusion at the airport results in two travellers, Han Seung-wan (Kim Jae-won) and Se Jin (Eugene), accidentally swapping passports.  Se Jin tracks Seung-wan down to his apartment and he agrees to return her passport on one condition – she must help him find his first love Lee Chang-young (Han Eun-jung).  She agrees to help him, only to discover that she has started a new relationship with someone else, Do-hyun (Lee Ji-hoon).  Heartbroken, Seung-wan seeks solace from Se Jin only to wake up the next day with a massive hangover and the other side of a one-night stand.

They quickly part ways, but a few weeks later, Se Jin learns that she is pregnant. She keeps it a secret from Seung-wan, but a year later, her sister decides to spill the beans at his engagement party. The discovery results in the two being forced to marry where they find out that adjusting to married life and parenting at the same time is quite a challenge.