Gray was introduced by being sent to capture Carmen on the train but ended up with them talking on the train ride through flashback.
Carmen and Graham first met while training in V.I.L.E academy. When Coach Brunt affectionately called Carmen "lambkins", Gray made fun of the name which resulted to Carmen dragged him by his shirt from behind and angrily telling him only her friends call her lambkins and he is to call her "Black Sheep", which he nods in surprise.
Later on, when the students get their rooms, Black Sheep was not amused with the fact Gray would be sharing a room with her but he seemed to be less mocking as before. In that moment, Sheena tried to touch Black Sheep's Matryoshka dolls, the only personal belonging she has had since she was a baby, to spite her but backed off when Gray stepped in which made Black Sheep trust him a bit more.
From then on, Black Sheep and Gray became friends as they trained through their thief classes. Gray was often impressed by Black Sheep's skills and was the first person to make her aware of how talented she was. Until Shadowsan failed Black Sheep on her graduation, Gray consoled her before having to leave with his team. Black Sheep, still determined, snuck on the air ride on Gray's next mission and when about to parachute down, she jumped on Gray as they hurled downward. Gray was in shock to see Black Sheep joined and she told him to not let go as they clutched onto each other, parachuting to safety. Gray scolded Black Sheep, bringing up how she could've put her safety and his mission at risk, which she is sorry for.
Black Sheep is made to stay back while they continue the caper until she sees when there is a witness at the sight, Gray is about to electrocute him until Black Sheep stops him. She screams at him, holding him off with his own tazer until she gets chloroformed, the last thing she sees is Gray's regretful face as she passes out. After that incident. Black Sheep left after seeing what V.I.L.E really was and rebranded herself as Carmen Sandiego, from the jacket she stole from Cookie Booker.
Gray asks Carmen to come back home, saying they miss her but Carmen can't go back, which means Gray has to finish his job reluctantly. Carmen outsmarts him, incapacitating him and leaving him on the train with her jacket on him. Gray gets captured by Interpol, interrogated by Chase Devaniux until V.I.L.E retrieve him and wipe away his memories for getting caught, brought back into society as a new man.
In the episode, "The Opera in the Outback Caper", Carmen sees Gray again in the opera house while she is trying to stop Le Chevre during the play "Carmen". Gray questions what she's doing backstage and doesn't remember the name Gray from what Carmen calls him (suspecting he is doing a cover as an electrician), calling himself "Graham" as he ushers her away. Carmen realizes he really doesn't remember her, to which Graham says with her fashion statement she would be hard to forget and says if there was a next time he would make sure not to make that mistake again.
Later on, Graham is found leaving the opera house as Carmen comes down behind him. Graham gives her an address to his favorite coffee shop and the time he comes there, implying he is asking her out on a coffee date. Carmen accepts and drops her name to him before leaving.
After her mission, she tries to catch up with her date with Graham and is talking to Player. Player brings up how he tried to capture her before and Carmen says this could be a second chance for them to become close again. Graham sees her against the billboard, the two smile at each other until Carmen disappears. Player asks why, and Carmen says whatever V.I.L.E did to him, he has a fresh start and she feels she may get in the way of that.
Fans got into the ship, some even seeing the relationship like a Mr. and Mrs. Smith story. Red Crackle had the appeal of two friends-to-enemies-to-lovers being separated on their paths after graduation.
Red Crackle has a rather sizeable fanbase behind it, liking the chemistry they had as friends and even as their current selves. There are some notable detractors, disliking Red Crackle because of Carmen in S1 calling Gray "a big brother" to her as well as believed age gaps and headcanons of Carmen being a lesbian and being shipped with Julia Argent. Some detractors compared it to Sheith, to which Red Crackle shippers point out the differences being they were both students when meeting, not meeting as a teacher and student like Shiro and Keith in VLD.
More fans have come since the release of S2 and more fanart of the pair keeps coming on Tumblr and Instagram.
- A theory was brought up in S1, which was Graham was humming to one of the songs from the opera "Carmen" which was on the lines of "love is a rebellious bird' which Carmen happening to be gliding down to him. There is even references of it in the episode, with Carmen in front of the billboard for the opera.