Mr. Plankton

Hae Jo, who runs an errand center, accepts Noh Yang-hui's request to kidnap her on her wedding day. Later, he unexpectedly runs into an old flame.

Hae Jo sets out to find his sperm donor, the biological father he never knew. He crashes Jo Jae-mi's wedding and drags her along.

Hae Jo recounts his first meeting with Jae-mi. While a huge fight breaks out at the sundae shop, Eo Heung and Wang Chil-seong's gang close in.

Jae-mi makes a tough choice between Hae Jo and her devoted fiancé. Soon they head down to Busan, while a mysterious figure arrives to bail Heung out.

Hae Jo spends meaningful time with Ko Jae-geun up in the mountains. Back in Seoul, Chil-seong corners Kkari and forces him to track down his old partn...

Heung reflects on his relationship with Jae-mi. After Hae Jo steals a boat to escape Chil-seong, they end up stranded on a deserted island.

Shaken by the island ordeal, Hae Jo slips into a slump his friend Yang Bong-suk can't lift. Meanwhile, Heung does everything to stay by Jae-mi's side.

Afraid of hurting Jae-mi again, Hae Jo tries to push her away. Later, he takes on a new errand and meets a young girl looking for her long-lost brothe...

After learning about Hae Jo's severe condition, Jae-mi is determined to help him find his biological father. But when she returns, he's gone.

Now alone with Heung, Hae Jo reflects on his unfortunate life. After a tense reunion at Kkari's workplace, Hae Jo decides to confront his painful past...