The Impossible Heir follows two friends whose dreams become intertwined as they begin working toward their common goal of social advancement. All episodes are now streaming on Disney+.
Warning: This article contains heavy spoilers
Plot summary
When high school student Han Tae-oh moves to his mother’s hometown, he meets Kang In-ha, the illegitimate son of the chairman of the Kangoh Group.
Tae-oh framed his abusive stepfather for his mother’s murder, who is still alive in a monastery, whereas In-ha faces neglect by his family as well as the townspeople.
Initially, the two boys do not get along. One day, after boxing together, In-ha offers to be Tae-oh’s friend, but Tae-oh suggests that the two of them become partners instead.
Tae-oh, who is a genius, promises to make In-ha his father’s heir. Tae-oh plans to gain success through In-ha, so he dedicates his life to In-ha’s success.
With Tae-oh’s help, In-ha gets into one of the top universities, where the two boys meet Hye-won, a girl they both start liking.
While Tae-oh does not pursue Hye-won, In-ha does. Similar to Tae-oh, Hye-won has no one to provide for her, works hard to lead a decent life, and aims to advance through In-ha.
Before Hye-won starts dating In-ha, Tae-oh asks her to be with him, but Hye-won, believing that they will regret giving up on their dreams of success, refuses.
Hye-won, too, is tempted to be with Tae-oh, as she reciprocates his feelings. Later, she goes to him, but by then, Tae-oh realizes that he does not want to give up on his dreams.
Over the next few years, Tae-oh, In-ha, and Hye-won, who is dating In-ha, work together to make In-ha the chairman’s heir.
Tae-oh and In-ha get jobs at Kangoh, while Hye-won works for a congressman. Eventually, Tae-oh proves his worth and manages to become the chairman’s right-hand man.
Tae-oh foils the schemes of the chairman’s wife, Geum-seok, and his second son, Seong-ju, to take over the Kangoh Group, which leads to the chairman publicly acknowledging In-ha as his son.
In-ha is now closer than ever to being his father’s successor. He also becomes engaged to Hye-won, who is accepted by the chairman.
However, trouble begins when Tae-oh is attacked by Mo Gi-jun, a man who works for the chairman’s older brother, In-ju.
This attack leads to Hye-won and Tae-oh realizing their feelings for each other, and they end up kissing before Hye-won marries In-ha.
Mo Gi-jun takes pictures of Hye-won and Tae-oh together, which are then used by In-ju to blackmail them, leading to Tae-oh agreeing to do whatever In-ju wants for Hye-won’s sake.
Tae-oh spends the night with In-ju and his mistress. The next day, he wakes up to find himself surrounded by their bodies, with no memories of the previous night.
In prison, Tae-oh discovers that Gi-jun is In-ha’s friend and that he murdered In-ju and his mistress to frame him .Tae-oh was drugged that night on In-ha’s orders.
In-ha is aware of Hye-won cheating on him with Tae-oh. He confesses to her that he only pursued her because Tae-oh liked her.
Once Tae-oh got him where he wanted to be, In-ha got rid of him. Hye-won finds herself trapped in an abusive marriage and seeks help from Tae-oh.
The two of them then begin working together, which is why In-ha plans to have Tae-oh killed in prison, but Tae-oh is rescued by the chairman, who has him abducted and brought to him.
Hye-won ultimately leaves In-ha when he confines her to a mental institution to manipulate her into siding with him. Hye-won still chooses to ally herself with Tae-oh.
As Tae-oh sets his plans in motion to thwart In-ha’s takeover of Kangoh by splitting it up, In-ha confronts the chairman.
The chairman had been aware all along of Tae-oh and In-ha’s partnership. He also knows about In-ha’s crimes and decides to fire him.
The confrontation between them results in the chairman’s health deteriorating, and In-ha leaves him to die. Fortunately, the chairman’s daughter, Hui-ju, finds him in time.
With the chairman in a coma, the battle to take over Kangoh is between In-ha’s faction and Geum-seok and Seong-ju’s faction.
Meanwhile, Tae-oh discovers evidence—a video on In-ju’s mistress’ phone—that proves his innocence and Gi-jun’s guilt.
With the help of a prosecutor Tae-oh had previously opposed, Tae-oh is proven innocent, while Gi-jun takes the blame for his and In-ha’s actions in the retrial.
In-ha decides to kill the chairman, but Tae-oh intervenes to save him. The two men acknowledge that they are no longer friends, marking the beginning of the final showdown between them.
Ending explained:
In-ha’s move
When Gi-jun, aware that he is facing a death sentence, gets scared, In-ha has him killed in prison to prevent him from becoming a problem.
In-ju’s wife, who is also a shareholder, chooses to support In-ha in the battle for the next chairman of Kangoh.
Tae-oh had founded a company named Gold H Investments, which now plays a crucial role in the battle for Kangoh’s takeover, as it holds a significant stake in the group.
Geum-seok, Seong-ju, and Tae-oh join forces to prevent In-ha from becoming the chairman, prompting In-ha to target Tae-oh’s family.
In-ha arranges for Tae-oh’s stepfather to be released from prison on parole, knowing that he will seek revenge against Tae-oh’s mother upon his release.
Tae-oh’s stepfather finds his mother, and their confrontation results in Tae-oh’s mother falling and suffering a fatal head injury.
In addition, In-ha provides evidence to the police that incriminates Geum-seok in corpse disposal and embezzlement, leading to her arrest on the day she planned to hold a press conference.
With Geum-seok and Seong-ju absent, In-ha addresses the press and declares a state of emergency, appointing himself as the acting chairman.
The congressman who previously supported Seong-ju then joins hands with In-ha’s faction, which includes Park Sa-jin, the chairman’s rival who had planned to split the Kangoh Group in two with In-ha.
Tae-oh is distressed by the news of his mother’s death, allowing In-ha to take advantage of the situation and get nominated as the permanent chairman.
Tae-oh’s countermove
Seong-ju attends Tae-oh’s mother’s funeral and asks Tae-oh to work with him, as both their mothers were harmed by a common enemy.
Seong-ju also confronts his mother. He is tired of living her dream; he no longer wishes to fight to be the next chairman.
Tae-oh’s mother left him a letter, urging him to let go of all past grievances and sadness. Tae-oh then gets back to work and resolves to stop In-ha before it is too late.
He promises the chairman, who is still in a coma, to protect Kangoh, and he keeps this promise.
In-ha calls an emergency meeting to hold nominations for the chairman. With the majority of stakeholders on his side, he knows that he will be the one who gets nominated.
However, it turns out that Gi-jun is still alive. He was rescued by the prison doctor, who contacted Tae-oh, as she knows him from his time in prison.
Tae-oh revealed to Gi-jun that In-ha ordered the attack on him and convinced him to turn In-ha in for In-ju’s murder and his own attempted murder.
As a result, In-ha is arrested before the meeting. Additionally, the prison doctor turns out to be Park Sa-jin’s daughter.
She tells her father that she had a history with In-ju, who mistreated her. She had to turn to drugs to cope with it. Park Sa-jin then decides to meet Tae-oh.
Tae-oh convinces Park Sa-jin to withdraw his support for In-ha. Tae-oh is willing to give him Kangoh Energy for a fair price.
In-ha, who no longer has any support, has his office raided by the prosecutor’s office, marking the end of his dream to take over Kangoh.
The end of a dream and the realization of another
The chairman comes out of the coma, and as it is Tae-oh who protected the Kangoh Group, he chooses him as his successor.
On the other hand, In-ha is disowned by the chairman. He receives a letter in prison, informing him that his surname has been changed from Kang to Baek, his mother’s surname.
After In-ha is sentenced to life imprisonment, Tae-oh pays him a visit. In-ha cannot give him an answer as to why he betrayed Tae-oh; he cannot remember anymore.
This is the last time In-ha and Tae-oh meet, as In-ha takes his own life in prison shortly after. Three years later, Tae-oh is seen visiting the columbarium where In-ha’s urn resides.
During these three years, the chairman’s dream project, Royal Road, is completed, with Tae-oh continuing to stand by his side. Hye-won is now working for the Korean President.
Seong-ju is the CEO of the Co-Prosperity Cooperation Centre, and he is happy with his role. Seong-ju’s relationship with Hui-ju has also improved.
Hui-ju is traveling the world, and Tae-oh’s loyal allies, who helped him take down In-ha, are rewarded for their efforts.
From his office in a tall building, Tae-oh watches the fireworks, reminiscing about his high school dreams of success. Tae-oh admits that he is still dreaming for himself.