"Mystery keeps calling mystery" so much that it can not be recovered. The story unfolds and clues in on the answers that would lead to the truth hidden in the main story; the suspense drama "Equation to Erase the Teacher"

In the year 1941 when Hong Kong was occupied by Japan, a Communist agent disguised as a military officer receives an important mission that is critical to the success of the revolution.

Ye Chong is a nationalistic young man with Communistic ideals. He comes to Hong Kong to help Sato build the presence of the Japanese military police in the area. In truth, he has sworn allegiance to his country long ago and secretly operates under the codename autumn cicada to relay Japanese intelligence to his comrades. His position puts him at risk time and again for the sake of his countrymen.

A sudden storm causes Chung Ting Kwok , a guerrilla fighter during the Second Sino-Japanese War, to awaken after being frozen for over seventy years. He discovers that he is now in the year 2018. He searches for his family, only to see his descendants behaving badly. His son Ho Woh Ping is fraudulently on welfare, while his grandson Ho Wing Nin uses feng shui to deceive people for money, yet Chung Ting Kwok is unable to correct them. Wayne even becomes involved in the romantic entanglement between the secretly wealthy Yung Chi Kiu, Chong Ho Sun, and wealthy businessman Tong Chak Ching . From covering up the truth of a murder to getting caught up in a battle for money, Chung Ting Kwok vows to save his family at any cost...

This drama is a love story between an 19-year-old man and 31-year-old woman, born in the same year and were childhood friends.

Although born in the same year, two childhood friends end up being 12 years apart because they have aged at different places (worlds) for some strange reason. Now Jung Jung Won (Lee Yun Hee) is a 31-year-old woman but Sung Hae Sung (Yeo Jin Goo) is still a 19-year-old boy. Meanwhile, Cha Min Joon (Ahn Jae Hyun) is a chef also interested in Jung Jung Won.

When children are not wanted by their parents, they are sent to the best boarding school in the country: “Home School”. However, Home School seems more like a prison than a school with its strict rules and regulations. Its curriculum is also quite unique.

A group of students in the school after starting to feel like something is very wrong with the establishment, try to find out just what is going on with the school in the woods. But this task is not that easy.

Bonus footage found on the DVDs of Keyakizaka46's 8th single 'Kuroi Hitsuji'. In Keyaki House we see the members spend unscripted free time with each other without their staff. The footage is divided into three parts, each part is in a different version of the DVD.

It tells the story of two childhood friends, Li Yi Mu and Xiong Qi Qi, who were born on the same day in the same town. Xiong Qi Qi is lazy and likes to stay at home, while Li Yi Mu is a serious perfectionist. Despite their contrasting personalities, Li Yi Mu stays by Xiong Qi Qi's side throughout her life, protecting her and guiding her to realize her dreams. Xiong Qi Qi also realizes Li Yi Mu's efforts and decides to reciprocate him with small acts of bravery and warmth.

Pimonpa will marry Traipope's father, even though his loving stepmother sick. So Traipope hate Pimonpa so much, even though he never met Pimonpa. Artorn who is ex lover of Pimonpa is sad about this. He try to contact her through her younger sister Pattaralada. On the wedding night, Traipope pretend to be Artorn, and send Pimonpa an appointment letter. Pimonpa very angry, she order Pattaralada to meet Traipope for her. When Traipope meet Pattaralada he misunderstand that Pattaralada is Pimonpa. So he took her away from the wedding so he can break his father wedding ceremony. Traipope take Pattaralada to the residence and he hurt and defame Pattaralada in several ways. When Pattaralada is gone her relatives worry about her except Piminpa. She did not report this to the police. Pimonpa and her husband went on a honeymoon and don't care about Pattaralada. Pattaralada will escape from Traipope. She put croton in Traipope food, but she poor Traipope. So, she take Traipope to hospital. Trai