The premiere episode of "Mr. Plankton" kicks off with a heart-wrenching scene that sets the tone for the series. Hae-jo, our protagonist, is found lying in the snow, his breath visible in the cold air, as he silently wishes to live. The desperation in his eyes is palpable as Jae-mi, a woman with a connection to his past, runs towards him, her scream echoing in the chilling silence.
The narrative then shifts to Hae-jo's current life, where he operates a peculiar business—fulfilling personalized requests that pique his interest. His next project comes in the form of a peculiar request from a woman who wants to be kidnapped from her own wedding. Despite the objections of his partner, Gi-ho, who is wary of the woman's gangster fiancé, Hae-jo takes on the job, intrigued by the challenge.
On the day of the wedding, Hae-jo makes a daring entrance, crashing the ceremony and spiriting away the bride on his motorbike. As they speed away from the scene, Hae-jo is hit by a wave of memories from his past, when he was abandoned by his parents. The flashback distracts him, leading to a bike accident that lands him in the hospital. Upon waking, he discovers that the woman has already fled to the airport, revealing that she had robbed her fiancé of his money and had orchestrated the entire escape.
In a tragic twist, Hae-jo learns at the hospital that he has inherited a rare brain disease from his biological father, one that has given him a mere three months to live. This news is a devastating blow, adding a sense of urgency to his life.
Meanwhile, we are introduced to Jae-mi, who is believed to be eight weeks pregnant, as she visits a jewelry store to have her groom's family heirloom ring resized. However, at the gynecologist, she uncovers a shocking truth: her groom had lied about her pregnancy to secure approval from his lineage-obsessed, 500-year-old family. The revelation is a double blow as Jae-mi soon learns she is experiencing early menopause, a condition that will prevent her from bearing children.
Overwhelmed by this news, Jae-mi has an emotional breakdown at the hospital, where Hae-jo, by chance, witnesses her outburst and learns of her plight. It is revealed that Jae-mi and Hae-jo had been in a relationship for three years, ending when Jae-mi's desire for children clashed with Hae-jo's reluctance.
Back at her in-laws' home, Jae-mi is gripped by fear, dreading the consequences of her family's discovery that she cannot bear an heir. In a moment of panic, she attempts to flee but finds herself unable to leave. The next day, she puts on a brave face as she prepares for her wedding, while Hae-jo, filled with anger and a newfound sense of purpose, decides to close his business and embark on a journey to find his biological father.
The episode takes a dark turn as the gangster, unable to accept that his fiancé had planned the escape, becomes determined to pursue Hae-jo and make him pay for "stealing" his bride. This sets the stage for a dangerous game of cat and mouse.
In a final twist, Hae-jo ends up at Jae-mi's wedding, with the intention of convincing her to leave with him, leaving the audience on the edge of their seats as the episode draws to a close. The first episode of "Mr. Plankton" is a rollercoaster of emotions, introducing complex characters and a gripping storyline that promises to keep viewers hooked for the rest of the season.