Kamisama Nanka Shinjinai Bokura no Eden

One day, the science-loving introvert Shikito Takai detects an overwhelmingly captivating scent emanating from his classmate, Kaito Nishio, whom he has always admired. Then, when Nishio becomes flushed and weak during gym class, Shikito attempts to escort him to the Nurse's office. However, they somehow find themselves in the disused equipment storeroom instead... This is the story of humanity's first Alpha and Omega, marking the beginning of the omegaverse.