Caitlin Snow was a S.T.A.R. Labs bio-engineer who was working there on the night of the Particle Accelerator disaster.
ARROW:
Caitlin and Cisco Ramon are doing an inventory of S.T.A.R. Labs technology at a S.T.A.R. Labs Warehouse in Starling City. She is working at the computer and criticises Cisco on how people don't use the word bomb in a cool sense of the word after he wanted to rechristen the warehouse "The Bomb." They begin to discuss the accident. When Cisco tells her was an accident, she says that he should "try telling that to the families of the people that died." However he tells her that she should "figure out how to tell it to herself." She just gives him a look and tells him that they need to just get the work done.
When they go to investigate who entered the warehouse, they are shocked to watch a security guard fall in front of them having been stabbed in the back by Deathstroke. They make a run for it with Deathstroke in close pursuit, telling them "the longer the chase, the slower the death." She asks Cisco to help her, going into a closed off pen where personal equipment to Dr. Arthur Light had been stored. Deathstroke arrives and pulls a sword on them. After they use a weapon to incapacitate Deathstroke, Caitlin opens the gate on the other side of the pen and the two escape.
Later Felicity arrives to check if they are both alright, having met them before on one of her journeys to Central to see Barry in his coma and him being moved to S.T.A.R. Labs after his condition deteriorated. She questions Felicicty after she refers to their attacker as "he" twice, asking if she knew who it was, but Felicity is quick to deny. She seems perplexed by her response. When John Diggle asks what was taken and if it was an industrial centrifuge, Caitlin tells them it's a secret and answers for Cisco that it is a secret too when he is asked. Felicity tells them she is happy to see they are alright, asking how Barry is doing, but Caitlin says he is doing the same as he was. She tells them that she will visit soon.
Later Felicity goes to a lab where both Caitlin and Cisco are working and tells them that she needs their help with something and saying that it will be "our" little secret, handing her a vial of Mirakuru for her to study and try to create a cure for.
THE FLASH:
