Club Friday The Series: It Happens on Valentine's Day - Season 1

Kim barges in to ruin Prae's Valentine's day dinner with Tan. To get back at Tan, Prae flirts with Wiwat, her boss, without knowing that Yuwadee, his wife, is watching from afar. Prae tries to convince Yuwadee that there is nothing between her and Wiwat, but Yuwadee refuses to believe her. Prae does not realize that Tan has agreed to get back together with Kim behind her back, while Kim leeches off Sira to solve her family's financial problem.

Wiwat announces that either Kim or Prae will become the department's manager. Both of them have three months to work on their achievements. Kim seduces Sira to help her with the promotion. Prae slowly approaches Wiwat, hoping the same from him. The competition is afoot and ramps up even further when Prae finds out Kim stole her client behind her back. Yuwadee agrees to help Kim attain the position in exchange for Kim helping her spy on Wiwat and Prae.

Kim secretly follows Wat and Prae with the guidance of Yuwadee. Due to Kim's interruption, Prae fails to close the deal with a client Wat has found for her. Prae steals an old client from Kim and chastise her in public. However, it turns out that Kim has taken a video of her and Wiwat together in Wiwat's hotel room during the seminar and she intends to get back at Prae with it.

Yuwadee pretends to not know about Wat's secret affair with Prae and threatens Kim to stay away from her family business. Prae reaches out to Tan, hoping to use his connections to get a client. Sira catches Tan wearing his watch but acts as if he does not recognize it. He later has someone follow Kim and finds out about her secret relationship with Tan. Yuwadee warns Prae not to test her patience.

Yuwadee suggests Tan see the truth for himself. They break into the hotel Prae and Wat are staying at. Wat begs Yuwadee to stay and announces that Prae means nothing to him. Sira confronts Kim and Tan and has both of them fired. However, the termination order is later intercepted by Sira's wife. It turns out she sent Tan to keep an eye on Sira.

Kim asks to stay with Tan as she has nowhere to go. Muenprae starts flirting with Sira at the office. Yuwadee takes Kim to see the major shareholder of the company. Tan and Kim are announced as the new managers of IT and Sales Department, respectively. Prae decides to resign from the company but the immense shock takes a toll on her and she starts seeing things.

The client wants to call off a big deal unless Muenprae is in charge of the project. The company then becomes hectic since she has already resigned. The situation is so critical that Madam has to make a disadvantageous deal with Sira and Muenprae. However, even after getting what she wants, Muenprae still feels unhappy.

Kim announces to everyone that Tan and she are getting married despite Tan's disagreement. The news upsets Muenprae so much that she has a severe mental breakdown and wakes up in the hospital. Tan tries to give her his support, but she doesn't seem serious about it. Sira becomes fed up with Madam and wants to start his own company with Muenprae on his side.