Leonard Singh, the founder of IMER, establishes the organization after a familial tragedy, aiming to revolutionize medical research. His son, Quinn Singh, feeling perpetually overshadowed, assumes the villainous persona of Dr. Centipede, utilizing a retractable poison-spiked suit to steal other scientists' work after murdering them. This path inadvertently leads to the accidental demise of his father, Leonard. Meanwhile, Dr. Silas Cross, once a colleague of Leonard's, harbors his own resentments and eventually seizes the opportunity to adopt the Dr. Centipede mantle after Quinn's retirement, exploiting the chaos to claim credit for Leonard's death.
Alongside this conflict, Joan Bradley, a brilliant genetic engineer recruited by IMER, rises to prominence for her groundbreaking work in creating man-made biological plants. She later becomes Hemlock, utilizing her tech to fight crime alongside her partner, James Dothon, who gains enhanced abilities through experimental serums, transforming into Instinct to combat the threat posed by a superpowered hitman called "the Butler" and Miscreant, a former scientist at IMER whose experiments went awry. The two eventually join the Odyssey after Darkhold becomes pure energy, becoming a pivotal part of the team and loved worldwide.
Hemlock eventually dies at the hands of Brainwasher, Instinct finds his own path in Tokyo as Nocturnal.