After getting rid of her biological dad, Sun-hui moves to Canada. Su-yeon gets released from prison after serving her sentence. Sun-hui returns to her parents, hoping they'll accept her as their daughter again. Meanwhile, Sun-hui writes a letter to her grandmother, inviting her to join an important family occasion.

Jin-hyeok arrests Hyun-min for impersonating him as a prosecutor. Hyun-min threatens Jin-hyeok to save him unless he wants to see Sang-ho dead. A fire breaks out at Hyun-min's paint store where Sang-ho is, but he doesn't make it out alive. Meanwhile, the grownup Sun-hui prepares a birthday feast for the late Sang-ho.

Hyun-min approaches Jin-hyeok with ill intentions and arouses his sympathy. With Jin-hyeok's help, Hyun-min sells insurance to Jin-hyeok's family and colleagues. However, he uses up all the money to gamble on horse races. In the end, Hyun-min decides to kill Sun-hui to get the money from her life insurance.

Sun-hui finds out the truth behind her adoption. Hyun-min sees Jin-hyeok and Eun-ju to tell them what exactly happened on the day Kyeong-ho's house was set on fire. The day Jin-hyeok met Hyun-min for the first time gets revealed, and Hyun-min's true intention comes to light.

Sun-hui is held by Hyun-min as he negotiates a deal with Jin-hyeok. While she is with Hyun-min, she learns that he wasn't really a detective as he has claimed to be. While Sun-hui learns more about her and Hyun-min's past, Jin-hyeok and Eun-ju tell the police about what has taken place.

Jin-hyeok is arrested and interrogated by the police after evidence was found in his car. However, he is set free as Su-yeon is seen again. Meanwhile, Sun-hui, Su-yeon, and Hyun-min find themselves in trouble as a hostage situation occurs and Sun-hui's place catches fire.

Sun-hui is shocked that her family bought peanut powder, which she is severely allergic to. After running away from home and asking Hyeon-u for help, Sun-hui gets into a car accident and starts to panic, fearing that her parents want to kill her. Meanwhile, evidence is found in Jin-hyeok's car, leading to an unfortunate turn of events.

Sun-hui grows more suspicious of her family after a van tries to hit her. She is told about the boy in the picture, and the man who introduced himself as her dad's relative turns out to be a police officer. Meanwhile, Su-yeon's belongings are found in the Han River, and Sun-hui begins to look for information on the Gongseo-dong Fire and Kidnapping Case.

After the encounter with her dad's strange relative, Sun-hui becomes determined to find out more about her family. With Hyeon-u's help, she sets out to uncover the mysteries of her family. As the two friends grow closer during this search, Sun-hui's parents try to stop their daughter from digging up too much.

Sun-hui is shocked that her cell phone and workbook are back in her room. Just then, Su-yeon comes over, demanding Sun-hui to turn herself in, and as soon as Sun-hui refuses her offer, she goes missing. Meanwhile, police officers questioned Kyeong-ho's friends from school and found out that stab wounds were the possible cause of Kyeong-ho's death.

Su-yeon is pained by the fact that Kyeong-ho has feelings for Sun-hui, and as he prepares to tell Sun-hui about it, he ends up getting killed. Sun-hui confesses to her mother that she may have killed someone and wants to turn herself in. However, her mother has other plans in mind.

A new transfer student arrives at Yunil High School. She is none other than Lee Su-yeon, Choi Sun-hui's best friend from childhood. The two have led vastly different lives over the past ten years, and Su-yeon reveals a secret to Sun-hui, who is shocked to hear what has happened to her best friend.