Triangle - Season 1

Jang Dong Soo is failing to catch Go Bok Tae and is now being questioned about his state of mind by higher ups in the Police Force, while Heo Young Dal is trying to steal/spam money to gamble.

Jang Dong Soo plans to use Heo Young Dal as a straw to discover a lead to imprison Go Bok Tae. Madame Jang takes over the loan from Oh Jung Hee and proposes a deal she can't refuse.

While Heo Young Dal and Yang Jang Soo are thinking of a plan to launder their money, Jerry tells them something worrisome. Oh Jung Hee bumps into Yoon Yang Ha, who invites her for a drink again.

Heo Young Dal saves Oh Jung Hee from being caught, but unaware that he became the main suspect by gangsters for the money that went missing. Close to death, he desperately rings Jang Dong Soo to save him.

Go Bok Tae gives Heo Young Dal a second chance when he sees something he likes. Jang Dong Soo receives a warrant to search and retrieve documents of one of Go Bok Tae's offices, while his adopted father requests him to stop with his search.

Heo Young Dal's gang finished their hell training, while Heo Young Dal has been commanded to finish Jang Dong Soo to be part of Go Bok Tae's real gang. Oh Jung Hee continues to feel uncomfortable with Yang Ha's presence around her.

Heo Young Dal sets a trap for Jang Dong Soo, but fails to complete it. Dong Soo retires from the police force and Go Bok Tae is about to start a war with Chairman Yoon.

After Heo Young Dal beats Yoon Yang Ha, he comes up with a new plan to take over Madame Jang's illegal casino in order to be recognized by Go Bok Tae. Dong Soo is now a loose cannon to frame Go Bok Tae.

After a successful cheat, Heo Young Dal invites Oh Jung Hee for a date to celebrate. In order to get Go Bok Tae's full trust, he requests him to scam the real casino. Go Bok Tae takes his revenge on Jang Doo Soo.

After receiving a call from Dong Soo, Heo Young Dal calls off the scam and takes a gamble to win money in a legal way. Yoon Yang Ha discovers about Jang Dong Soo's past.

Heo Young Dal is sentenced to prison with his friends in which another nasty surprise is awaiting them. Jang Dong Soo continues to find the exact details of the death of his father and is eager for revenge. Oh Jung Hee visits Heo Young Dal in prison and opens up.

Dong Soo has been imprisoned by Yoon Yang Ha and is out for revenge and asks Young Dal for advice. Young Dal discovers the true identity of the old man he cared for in prison, but is embarrassed to return to Oh Jung Hee's house once released.

Go Bok Tae and Yoon Yang Ha are worried when Young Dal is living quietly. Young Dal requests his hidden card, while Shin Hye helps him to remember his past.

Shin Hye is trying to help Young Dal to recover his lost memories. Young Dal wants Dong Soo to represent Ahn Chang Bong. Yoon Ha explains his true feelings towards Jung Hee and will not stop to do so.

Dong Soo is hospitalized and is in coma. Young Dal decides to replace Dong Soo as Chang Bong's guy and Yoon Yang Ha explains his past to Jung Hee.

Young Dal has been introduced to Daejung Casino as the new director. Jung Hee tells Young Dal that she will not forget him, but is going to wait for him. Dong Soo awakens from his coma.

Yoon Yang Ha has been demoted due to his lost, while he creates a plan to retake his position. Go Bok Tae calls in a favour from topdog Han Myung Jae to deal with Heo Young Dal and Dong Soo. Jung Hee has been kidnapped.

Young Dal has been backstabbed by Yoon Ha and has to act like a thug in order to protect Jung Hee. Myung Jae pays a visit to Mrs. Min and Man Bong. Shin Hye finds out about Dong Soo's youngest brother.

Shin Hye is convinced Yang Ha to be Dong Woo and is looking for confirmation. Young Dal and Jung Hee both receive a photo from their childhood, but unaware of each identity that time. Young Dal plans to destroy Myung Jae without a single drop of blood.

As Young Dal plan is working out, Myung Jae shows up at the Casino with an unlimited bet against Madam Min.

Dong Soo tells Young Dal that Yoon Ha is his younger brother, while the opportunity to bring down Chairman Yoon and Go Bok Tae has arrived. Jung Hee asks Young Dal to leave Yoon Ha alone and try to avoid him. Yoo Jin asks Yoon Ha to show her any form of sincerity in order to forgive him.

Yang Ha has been told his true identity, but denies their relationship. Go Bok Tae sends his men to finish Young Dal, while Yoo Jin offers Young Dal a deal he can't refuse to partner up.

When Chang Bong is in critical condition, Young Dal does not trust the accident and asks Dong Soo to look into it. Yoon Ha is trying to get rid of Young Dal, but it is going to be a tougher battle than he initially thought due to a precautionary action of Chang Bong.

Pil Sang has been arrested, while Dong Soo receives news about the death of his biological mother. Jung Hee supports Young Dal through this difficult time, while Shin Hye tries to convince Yoon Ha to visit his mother's funeral.

Young Dal makes a bald move to remove Go Bok Tae from his current position and to gain more power within Daejung Group. Yoon Ha's life is in danger.

After a tragic loss for Young Dal and Dong Soo, they come up with a plan to dismantle Go Bok Tae, Chairman Yoon and Pil Sung from their position in order to stop their greed.