|“||How do you sleep at night, knowing you destroyed so many lives?||„|
|~ Griffin Grey to Wells|
Griffin Grey ambushes Harrison Wells after he has unsuccessfully tried to persuade his daughter to return. He steps onto the street right in front of Wells' car who is driving at full speed. Although Wells hits the brakes, the car smashes into Grey who due to his strength is completely unaffected. Wells is knocked out during the crash and Griffin Grey takes him and drags him with him. Cisco is alerted almost immediately and tells Barry.
Back at his lair, Griffin Grey introduces himself to Wells and reveals that he is one of Wells' "accidents". He orders Wells to fix what the particle accelerator did to him, revealing that the incident provided him with inhuman strength. Wells tells him that this strength hardly seems to be a problem. Griffin claims that he once thought so too but reveals that despite his he is only eighteen years old, the accelerator incident causing him to age rapidly. Grey claims that, should the aging continue, he would be dead in a few months and threatens to kill Wells should he be unable find a cure.
Cisco eventually tracks down Grey who is breaking into Ace Chemicals. Although Barry, Cisco and Joe try to arrest him, he lunges barrels full of explosive liquids at them. Barry, used to be able to use his speed to dodge projectiles, is hit and knocked down. At that moment, Grey ages visibly and flees from the facility. Back at S.T.A.R. Labs, the team realises that the more Grey exhausts himself, the faster he ages.
While Wells creates a antidote, Griffin tells him that he once had a girlfriend who now doesn't recognize him anymore and asks him how he is able to sleep peaceful at night.
Barry and his team track Grey down to an abandoned amusement park. Before he heads there, Barry is told that without his powers, he can only withstand one of Grey's punches. Back at the amusement park, Grey finds out that Wells has no way to save him. Angrily, he attacks Wells but stops when he is alerted to Barry's presence. On his way out, he is attacked by Barry. He attacks Joe by throwing a car at him, visibly aging once more. Although too old to safely use his powers, Griffin punches Barry three times more, causing him to age to death. In death, his body reverses the aging and his corpse is once more the body of an eighteen year old.