[HELIOS] It's been a while since the 13th training team began... The North Sector, which boasted an undisputed No. 1 ranking in the [Sector Rankings], finds itself in an unexpected predicament. Marion, the youngest mentor in history, is deeply hurt by North's drop in ranking, and is unable to control his emotions, becoming frustrated. The other mentor, Victor, is only interested in researching [Substance]. While rookie Gast struggles to rebuild the team, fellow rookie Ren is obsessed with revenge against [Eclipse], who killed his sister and parents. The team is far from united. As if reflecting the team's fragmented situation, the city's security deteriorates, and trouble breaks out one after another. To make matters worse, an [Eclipse] entity known as "Zero" begins appearing in the North as well...