Sometimes, Chas, Constantine's remarkably hard to kill pal, can be a bit of a nonentity, someone who goes along with John's plans with far less angst than most. But when the soul of Chas' daughter is stolen, we finally get to see what the cab-driving sidekick is capable of.
Now that we've gotten a little more background on Zed within the confines of the TV show, it's Chas' turn for backstory. We meet Renee, Chas' ex, and their daughter Geraldine, and learned how working with John gradually separated him from them. Once upon a time, Chas died in a fire, as did several dozen other people (in a reference, it seems, to the tragic Station nightclub fire in Rhode Island). Thanks to a spell a drunken John had cast on him just minutes earlier, Chas absorbed the life force of all the people who died, so that he will experience one death for each life he absorbed. Chas isn't precisely unkillable; it just will take him a really, really long time to stay dead.
Chas, it turns out, is one of those "with great power comes great responsibility" types, and he uses his extended mortality to save other people. The problem is that demons and monsters don't bother to schedule their schemes around kids' birthday parties. Even though it's sad that Chas has to make the choice between his family and his moral obligations, it's nice to see someone on Constantine who just makes their decision and accepts it. (Okay, granted, he doesn't have the whole sent-a-kid-to-Hell business weighing on his conscience, but it's still nice.)
When Geraldine falls into a mystical coma, however, it looks for a moment like Chas is willing to sacrifice it all — not just his own life, but also his ability to save other people's lives. When people start falling into inexplicable comas across New York, John quickly learns who is behind the affliction: Felix Faust, who is, quite appropriately, a second banana himself — always a dark magic bridesmaid, never a bride. Now, however, he is determined to slurp up power for himself using a boatload of souls stolen from the comatose.
So while Felix Faust tries to step out of his hench role to become the starring villain, Chas must be John Constantine. While Zed and John try to deal with Faust's handiwork themselves, Chas offers Faust something juicier than Geraldine's soul: the 31 souls he's still harboring in his own body. But while it looks like Chas is going to take himself out of the game permanently, he actually has something better in mind. He uses a trick from Constantine's playbook (deception) and one of John's actual mystical items (Achilles' tendon) and a little something of his own: a grenade. Chas and Felix Faust both go boom, ending Felix's spell. Oh, Faust, you really shouldn't be alone in a room with a pissed-off father who can come back from the dead.
As if Chas needed to be more lovable after all that, he ends the episode by remembering his soul donors. He doesn't just use his additional souls to save people; he also honors the people the souls belonged to. He keeps a scrapbook of the people who died in the fire and tells Geraldine about them to keep them alive. Geraldine's soul isn't mere currency, and to Chas, neither is anyone else's.
John also gets his own "Aww" moment, although I'm not sure what it's doing at this point in the show. At one point, Zed communes with the spirit world in order to speak with the comatose Geraldine. It proves a dangerous move, but as Zed recovers, she tells John that she spoke to his mother and that Mama Constantine said John wasn't responsible for her death. Huh. In the pilot, John said that he desire to connect with his mother was the driving force behind his mystical dabbling. And now he's made a connection, albeit in an indirect way. Is this a sign that John may ask Zed to commune with his mother in the future? Or did the writers want to make sure John got some solace in that department before the show ends?