With their son, Seon-ho, fighting for his life, Park Mu-jin and Kang In-ha challenge the authorities, who dismiss his accident as a suicide attempt.
Frustrated with the police, Seon-ho's parents start digging for evidence themselves. Seon-ho's sister, Park Su-ho, gets into a fight with a classmate.
With damning evidence that her son was mistreated, In-ha approaches the school board and the perpetrators' moms -- who are busy protecting their young.
O Jun-seok meets a witness that puts him with Seon-ho on the roof that day. Su-ho visits Jeong Da-hui, and Seo Eun-ju begins to doubt her own son.
In-ha deduces that someone tampered with the scene of the accident. As the investigation grows more intense, it takes a toll on friendships.
With Seon-ho on the verge of consciousness, his family finds hope while Jun-seok grows fearful. Su-ho starts a nationwide petition for her brother.
In-ha grows increasingly suspicious of Eun-ju. Su-ho learns that Han Dong-hui may have been what drove a wedge between Jun-seok and Seon-ho.
Dong-hui reveals the darker side of Jun-seok's character, while O Jin-pyo finds more evidence to hide. In-ha receives a cactus from the security guard.
Eun-ju learns what triggered the fight on the roof, while In-ha uncovers the first of Eun-ju's many lies. The police finally get busy.
Mu-jin seeks the help of the school security guard. Jin-pyo moves fervently to suppress the allegations against his family.
With harsh accusations made against her son, In-ha faces the same dilemma that befell the other parents. Eun-ju confronts her husband.
The police show up on Eun-ju's doorstep. In-ha tries to clear her son's name. The truth behind the love triangle surrounding Da-hui is revealed.
The hit-and-run further fuels the investigation as pieces of the puzzle begin to come together. Dong-hui finally stands up for herself.
Mu-jin uncovers the mystery beneath the cactus, and the police narrow in on Jun-seok's family. The legitimacy of Da-hui's claim is still in question.
What's great news for some may be bad news for the guilty -- or could it be a second chance? Eun-ju realizes that to protect her son, she must escape.
Jun-seok turns himself in, taking the blame for his parents' crimes. Da-hui comes forward with her testimony. Eun-ju searches for the "smoking gun."