Caitlin Snow also known as Killer Frost is a highly intelligent bio engineering expert scientist who works at S.T.A.R. Labs Central City Branch. She is also from Central City as well she recently lost her fiance Ronnie Raymond during the recent explosion at S.T.A.R. Labs with The Particle Accelerator.
Meeting Felicity Smoak
In The Aftermath of The Event with The Particle Accelerator and the loss of her fiance she worked with S.T.A.R. Labs to help deal with situations that The Event caused. One of situations was Barry Allen's accident, causing him to fall into a coma she and her friend and co worker Cisco Ramon met and became friends with Felicity Smoak during one of her regular visits to see Barry Allen while he was in a coma.
One Night in Starling City
As a result of The Event with The Particle Accelerator she and Cisco Ramon were assigned by their boss Harrison Wells to go to the Starling City S.T.A.R. Labs Warehouse Branch and pack it up and move it all back to Central City's S.T.A.R. Labs Branch. While doing inventory and talking about The Particle Accelerator Event the two of them all of sudden heard some noise and movement within the warehouse. The two investigate and found a security guard Cisco Ramon tried to assure they were almost done however the guard continued to stare at them a little to long creeping the both of them out. Before the guard could reply back to them he starting spurting blood then dropped dead revealing Deathstroke who had killed him. The two quickly run for it only to be still followed by Deathstroke they soon manage to use an old energy gun created by Former S.T.A.R. Labs Member Arthur Light who was insane and fired by their boss Harrison Wells to briefly take out Deathstroke allowing both of them to escape to safety. After reporting the attack by Deathstroke she and Cisco Ramon met Felicity Smoak and John Diggle at the hospital to ask them about the attack. Felicity Smoak also asked them both about how Barry Allen's condition and how he was doing she tells Felicity Smoak he's the same but Cisco Ramon mentions he's been visited by Iris West which makes Felicity Smoak not feel so good. Some time later Felicity Smoak comes to see them and ask for her and Cisco Ramon help in creating a cure for The Mirakuru.