The Death Stench in the air is the 2nd chapter of Gyo.
Tadashi kills the first death stench (who came to them) by pushing a cabinet. He puts Death Stench that inside a plastic. However, Kaori had a sense of smell. She can smell the scent of a death stench. Later, She became sick. But then the death stench in the plastic is gone. However, It enter the room and chased Kaori to the city.