Due to the growing number of Inhumans during the Inhuman Outbreak, and with S.H.I.E.L.D. being publicly labeled as a terrorist organization, US President Matthew Ellis created a new agency, the ATCU, and appointed Rosalind Price at its head, with the purpose of locating and containing the Inhumans.
One of these Inhumans, Lincoln Campbell, attempted to live a normal life in Cincinnati following the dismantlement of the Afterlife settlement. However, Campbell was found by Lash, a monstruous Inhuman who chased other Inhumans with the intent of killing them. Lash attacked Campbell, who received the assistance of S.H.I.E.L.D. However, Campbell was forced to use his powers during the fight, which was witnessed and recorded on the Cincinnati Memorial Hospital's security feed. Campbell turned down S.H.I.E.L.D.'s offer to join them and ran away, chased by the ATCU.
The ATCU located Lincoln Campbell and Luther Banks led a team of ATCU operatives to chase him. As they were closing up on him, Campbell used his powers to damage a high voltage electricity line, keeping the ATCU from chasing him. As a result, the head of ATCU Rosalind Price informed all authorities, from local police departments to the FBI, that they were hunting a fugitive. S.H.I.E.L.D. was informed of the manhunt and decided to step in to protect Campbell.
Using a tracking device Alphonso Mackenzie had implanted in Campbell when Lash attacked him, S.H.I.E.L.D. contacted the Inhuman and Daisy Johnson offered to help him. However, Campbell refused S.H.I.E.L.D.'s assistance and hung up on Johnson. He then got rid of his tracker and destroyed his phone so that no one could track him down.
Campbell took a night bus, hoping to go to safety, but when his picture, which had been disclosed to the public by the ATCU, was displayed on the bus' TV, he used his powers to shut down the power in the bus. One passenger, Private Brown, recognized Campbell and attempted to arrest him, but Campbell managed to escape and tried to find another way to remain far from the authorities.
Campbell sought the help of his friend John Donnelly, who agreed to pick Campbell up and took him to his apartment in Chicago. Campbell swore to Donnelly that he had not done anything wrong and that he was not dangerous. Initially, Donnelly chose to believe him, but then he heard a news report about Campbell stating that the Inhuman was extremely dangerous and asking to contact the authorities if he was being spotted. As a result, Donnelly secretly called the ATCU.
Meanwhile, Phil Coulson contacted Price and offered that the two of them met so they could find an arrangement regarding Campbell.
Discovering that Donnelly had called the ATCU, Campbell decided to leave his friend's apartment. However, Donnelly attempted to keep him from doing so by threatening him with a baseball bat. Campbell used his powers to disarm his friend, but this caused a heart attack for Donnelly who died despite Campbell's attempts to reanimate him. Desperate and in danger, Campbell called Johnson and S.H.I.E.L.D. for help. He then hid in a nearby building, awaiting for assistance while Banks and his men unsuccessfully searched Donnelly's apartment.
Johnson found Campbell and comforted him, telling that she was willing to do anything to help him. After the two shared a kiss, Campbell agreed to go with Johnson. However, Alphonso Mackenzie joined them with Banks and the ATCU, and revealed that Coulson had agreed to let the ATCU take Campbell into custody. Refusing this fate, Campbell used his powers to knock over the ATCU operatives and fled once again.
Banks revealed that their target had switched from Campbell to Johnson, but Coulson convinced Price to let her go, claiming that if the ATCU took S.H.I.E.L.D.'s Inhuman asset, he would devote all S.H.I.E.L.D.'s resources into crushing the ATCU. Price reluctantly agreed to let Johnson and Campbell go in exchange for Coulson's expertise.
Despite Daisy Johnson's disapproval, the chase of Lincoln Campbell opened a collaboration between S.H.I.E.L.D. and the ATCU so that Phil Coulson could guide Rosalind Price into fighting against the real threats, such as Lash, instead of chasing potential assets like Johnson or Campbell. Though Coulson and Price initially treated each other with distrust, they eventually learned to fully collaborate and even entered a romantic relationship.
Campbell remained on the run for a little while, leading his own investigation regarding Lash, whose killing spree kept going, for example with the Assassination of Shane and Lori Henson. Campbell eventually figured out that Lash could only be someone within S.H.I.E.L.D. He agreed to collaborate with the agency, which discovered that Lash was actually Andrew Garner, and ultimately joined the Secret Warriors, a team of Inhumans gathered and led by Johnson.