Zatímco skutečný Nam Sin vyrůstá se svým dědečkem, jeho matka vytvoří Nam Sina III, který vypadá a chová se jako člověk, ale je to robot.

Nam Sin III hned první den v roli Nam Sina zaskočí na firemní akci Seo Jong-Gila a setká se s Kang So-Bong, bývalou osobní ochrankou, která k němu cítí zášť.

So-Bong se vrací do své staré práce a špehuje kolem pro Jong-Gila. Ji Yeong-Hun a O Ro-Ra se mezitím snaží ochránit své tajemství.

So-Bong je blízko odhalení pravdy o Nam Sin III - ale on je o krok napřed. Jong-Gil spřádá další zákeřný plán.

Po velkém odhalení si So-bong balí kufry, ale je pro ni těžké odejít. Mezitím Nam Sin III má nařízeno, aby se oženil se Seo Ye-na.

Ye-na se odmítá vzdát. So-bong a Nam Sin III se dohodnou na novém řešení. Jong-gil zaslechne důležitou informaci o Nam Geon-hoovi.

Jong-gil se snaží převzít moc ve firmě a dostává se do problémů s Geon-hoem. Ye-na se náhodou něco dozví.

Ye-na nakupuje svatební šaty. Yeong-hun se potýká s pochybnostmi o jeho pohnutkách. So-bong vyslechne znepokojivý rozhovor.

Když se Nam Sin III odchýlí od svých naprogramovaných pravidel, So-bong ho začne vidět v jiném světle - a Ro-ra zvažuje, co dělat.

Nam Sin III se rozhoduje sám. Ye-na odhalí pravou povahu svého otce. David se setkává s tajemným mecenášem projektu.

Ro-ra se potýká s těžkým rozhodnutím. Ye-na konfrontuje Jong-gila, který si je jistý, že se děje něco divného.

Nam Sin III se setkává tváří v tvář s Nam Sinem. So Bong a David se společně snaží změnit Ro Rain názor.

So-bong radí Nam Sinovi III, aby se držel od Nam Sina dál. Geon-ho se připravuje na předání své funkce a zkouší své potenciální nástupce.

Když se Nam Sin vrací ke svému každodennímu životu, snaží se smířit s existencí Nam Sin Ill a vzbudí pozornost, když se navrátí jeho stará osobnost.

Nam Sin III, který je proti své vůli nucen chovat se jako Nam Sinova loutka, bojuje za svou svobodu. Ro-ra zjistí Davidovo tajemství

Nam Sin se snaží získat Geon-hoovu podporu. Yeong-hun hledá pomoc u Nam Sina III, který potřebuje trochu povzbudit od So-bong.

Yeong-hun a Nam Sin III na schůzi akcionářů udělají překvapivé prohlášení. Nam Sin se dostane k nebezpečnému zařízení.

Když se Jong-gil pokusí o poslední převzetí moci, stojí Nam Sin III před volbou, zda zachránit Nam Sina, nebo se rozloučit se So-bong.

Namsin leaves the wedding ceremony on his own to save So Bong. After saving So Bong, he chases after Jong Gil's agent. Laura become furious because Namsin keeps getting out of control. Meanwhile, Laura and Young Hoon are shocked to hear that Nam Sin isn't showing any progress and is becoming a lost case.

Jong Gil gets more and more suspicious about the true identity of Namsin. Namsin tries to know more about So Bong after becoming friends with her. Laura is troubled as Namsin gets completely out of her control. Meanwhile, something happens at the hideout while nobody is looking.

Laura is overwhelmed with joy as she finds out that Sin is getting better. However, she gets more nervous as Namsin continues to make decisions on his own. Ms. Jo tells So Bong that she has a video of Namsin breaking down a car with his bare hands and demands answers to her questions. Meanwhile, Laura tries to hide the truth about Sin getting better from So Bong and Namsin.

So Bong is upset to see Namsin continuing to listen to Laura without knowing that he has a kill switch installed in himself. Jong Gil finds where Ye Na is and tries to get into Laura's house. However, this causes Ye Na to panic and do whatever she can to keep Jong Gil away from Nam Sin.

So Bong confesses her love at the presentation, but unexpected events continue to occur. Nam Sin sees Laura after 20 years, but he acts coldly to her since he is angry about the very existence of Namsin3. Meanwhile, So Bong tries to negotiate with Laura to take away the kill switch from her.

After hearing So Bong's love confession, Namsin tries harder to understand and feel emotions. However, Sin is more frustrated after meeting Namsin and starts to wonder what Laura really thinks about Namsin. Meanwhile, So Bong's dad, Jae Shik, is shocked to realize that his daughter is in love with a robot.

Nam Sin becomes more and more angry as he gets rejected by So Bong and realizes how Laura really feels about Namsin. This makes him call Jong Gil to the hideout. Namsin and So Bong return to their daily lives. Meanwhile, Chairman Nam invites Namsin to discuss about when and how he will give him his position.

Nam Sin knows that everyone has done what they did for his own good, but he gets so angry that he says harsh things to Young Hoon. Chairman Nam offers his position to Young Hoon to see what he thinks, but Young Hoon's reply wasn't what he expected. Meanwhile, So Bong decides to never leave Namsin's side.

Nam Sin feels threatened by the robot Namsin and decides to go to work even if he hasn't fully recovered yet. So Bong continues to work as Nam Sin's bodyguard to protect Namsin. However, Nam Sin has his own reasons to go to work. He tries to find something without telling even Young Hoon about it.

Nam Sin becomes angrier as he continues to find Namsin's traces everywhere he goes. He tries to get rid of such traces and find a way to make Namsin get in trouble. Chairman Nam calls Namsin, and Namsin visits David after hearing shocking news. Meanwhile, Nam Sin overhears the conversation between Namsin and David.

Nam Sin becomes furious as he realizes that Chairman Nam has known that he had been replaced by a robot. His anger leads him to ask Laura if there would be any way for him to destroy Namsin. Laura tries to avoid the situation, but she ends up giving him access to the manual mode as he demands.

Jong Gil calls out Nam Sin by saying he has something to tell him. Another error occurs in Namsin's system, and he sees a hallucination of So Bong. This makes him unbearable to hold back anymore, so he goes to see So Bong. Meanwhile, Nam Sin tries to get back at Chairman Nam after hearing a recorded message from Jong Gil.

Nam Sin abuses the manual mode and makes Namsin attack Chairman Nam. However, things don't go as Sin has planned. Jong Gil overhears that Chairman Nam really does have dementia and tries to come up with another plan by pretending to help Nam Sin. Meanwhile, Young Hoon is furious that Nam Sin had tried to kill his own grandfather, and Laura becomes desperate as Nam Sin keeps going too far.

Nam Sin makes Chairman Nam sign the stock transfer agreement papers and becomes the new chairman of PK Group. However, Young Hoon suddenly returns to Nam Sin's side and blocks of Jong Gil. After returning, Young Hoon carefully sets up a plan to make things go back to where they belong. Meanwhile, Laura is invited to the company by Nam Sin.

So Bong prepares a surprise party for Namsin3. Jae Shik takes Namsin3 to a spa, and Namsin3 picks up his gift for So Bong. Nam Sin finds the kill switch and tries to destroy Namsin3, but Laura gets a call from Ye Na and tries to stop him. Meanwhile, Jong Gil finds out that Nam Sin, Namsin3, and Laura is heading to a construction site and follows them.

Namsin3 gets framed for murdering Laura and goes into hiding with So Bong. Nam Sin get heartbroken by hearing that his mother is dead. Ye Na's instincts tell her that something is suspicious about her father, Jong Gil, and tries to find out what it is. Meanwhile, Jong Gil visits the office and meets Young Hoon.

Namsin3 realizes that the kill switch has been reactivated and tells David about it. So Bong ends up finding out about this as well and tries to stop Namsin3, but Namsin3 insists that he must save Nam Sin. Meanwhile, everyone is out to search Namsin3 and Nam Sin, but Jong Gil refuses to give up so easily.