Plot of TWICE

Synopsis
Following the discovery of the Overtone after the nuclear bombs dropped on Hiroshima and Nagasaki at the end of World War II, several paramilitary mercenary groups called Legions rose to power around the world. Within twenty years, Legions have supplanted the majority of the world's militaries with IDOLs, hybrid super-soldiers and media celebrities with dedicated fan bases. IDOLs are trained in the use of manifesting the Overtone into powerful Concepts to devastating and spectacular effect. The spectacle of Concepts has given rise to multiple televised IDOL tournament circuits around the world where IDOL groups compete against each other in dangerous (often lethal) gladiatorial matches. These IDOL tournaments are used for political gain and mediating international disputes, replacing the conventional ideas of warfare around the world.

In the year 2015, dissent grows around the world with how IDOL tournaments decide certain global issues. Ancient international tensions rise between the two nations at the forefront of IDOL development: Japan and Korea. New powers rise, old powers struggle to maintain the balance, and the threat of open war again looms over the horizon.

An international group of nine female IDOLs, TWICE, will determine the balance.

Season 1 (SIXTEEN)
JYP Legion recruits IDOL trainees from throughout the Eastern hemisphere to come to Korea to train. Every five years, the Legion holds a tournament to determine which of these trainees are worthy to become IDOLs. Their trainees undergo many rounds of testing and trials. Only sixteen trainees chosen by JYP Legion IDOLs make the televised final tournament, in which they don Suits and experience the full dangers of IDOL combat. The grueling tournament is called SIXTEEN by viewers, named for the sixteen who are chosen to enter.

Several notable trainees progress through the trials to enter SIXTEEN: Momo is eliminated early in SIXTEEN by Thai trainee Natty. Minyoung is eliminated in the final round, breaking the bonds of 6-MIX and causing Jeongyeon to lose her confidence. The final seven contestants to become TWICE are Nayeon, Jeongyeon, Sana, Jihyo, Mina, Dahyun, and Chaeyoung. In a shocking reveal, JYP's Centurion, Park Jinyoung announces he is adding two additional members: eliminated contestant Momo, and 9th place contestant Tzuyu. Despite placing 8th, Somi is not added to TWICE and resumes being a trainee. She begins to grow resentful towards JYP Legion.
 * A group of Korean trainees (6-MIX) who failed to enter the final tournament five years ago (Nayeon, Minyoung, Jeongyeon, Jihyo)
 * A group of Japanese trainees (Momo, Sana, Mina)
 * A group of rookie trainees who have yet to complete high school (Dahyun, Chaeyoung, Somi)
 * A Taiwanese Visual trainee (Tzuyu)

Season 2 (Korean Circuit)
Rookie IDOL group TWICE enters the Korean Circuit in order to bring more prestige to JYP Legion. They find multiple obstacles impeding their progress: rival female groups that threaten to destroy them, an introduction to the overwhelming power and influence of male IDOL groups, and the political repercussions from an IDOL's successes.

Tzuyu becomes caught in a political game between China and Taiwan, which threatens TWICE's gains in the Korean Circuit.

Meanwhile, the Stone Combine is formed by several lesser Legions who pool together their resources to create a super IDOL group, IOI. JYP Legion sends a trainee, Somi, to join the Stone Combine to investigate their involvement. Somi inadvertently becomes IOI's ace IDOL as IOI threatens to take over the Korean Circuit.

Season 3 (The Nation's Girl Group)
Rising through the charts on the Korean Circuit, TWICE must battle rival female groups (Red Velvet, GFriend, IOI) for the title of Nation's Girl Group. Jeongyeon and Mina struggle with hiding their budding relationships with male IDOLs. Jihyo loses her resolve as an IDOL, and Nayeon seeks to establish herself as TWICE's new leader. Chaeyoung becomes tired of TWICE's Concepts, and wants to leave the group to find her own path.

YG Legion forms Blackpink, a female IDOL group specializing in the new Concept form known as Girl Crush. Girl Crush Concepts begin to take over the Korean Circuit and beyond, and a rapid shift in Concepts occurs throughout Korea.

Season 4 (Japanese Circuit)
After receiving the title of Nation's Girl Group, TWICE's Japanese members receive a request to return home amidst the increasing tensions between Japan and Korea. International rivalries flare as Korean politicians blame the Japanese for horrors committed during World War II. The members of TWICE, reluctant to split after finally achieving their goals in the Korean Circuit, make the choice to enter the Japanese Circuit together with the end goal of unifying the IDOL industries of Korea and Japan.

In Japan, TWICE realizes their supposed mastery of Color Concepts was just the tip of the iceberg. Japanese Legions AKB, Flower, and Exile block their progress and demonstrate new Concepts they have never experienced before. Momo, Sana, and Mina's national loyalties are tested. Sana, once a former Exile trainee, struggles with loneliness as Momo and Mina both meet with their families. Her former friends on the Exile IDOL group E-Girls convince her to leave TWICE and join them in the upcoming Oricon Tournament. Handicapped with one less member, TWICE learns how to diversify their Color Concepts and adopts manifestation techniques from Japanese underground IDOLs, Babymetal.

Season 5 (The World Circuit and the New Generation)
Male IDOL group BTS breaks into Western Circuits, dominating tournaments and proving that Eastern IDOLs can compete with Western Bands. IDOL groups from Korea and Japan begin flooding the Western Circuits, and a united World Circuit is created. The competition becomes global and political stakes become greater. TWICE struggles as their Concept is not effective against Western Bands, while Blackpink's Girl Crush proves powerful in Western tournaments.

After a violent conflict with members of Twice, JYP Legion's Somi defects to YG Legion and begins to train in Girl Crush Concepts.

Meanwhile, a new generation of IDOL groups is born in the East. JYP Legion's new rookies, Itzy, joins TWICE in their fight on the World Circuit, and the Stone Combine reveals IZONE, a combined group of Japanese and Korean IDOLs who threaten to take over TWICE's position as Nation's Girl Group.