The River Styx in Greek mythology is the last barrier that has to be crossed by the souls of the dead to reach the Underworld.
However, there was always a price to be paid for safe passage so it's incredibly apt that Mary Kills People Season 1 Episode 2 was named for this particular body of water.
And speaking of water, that is definitely one of the pervasive themes in this episode.
Beginning with an energetic yet somehow foreboding seniors' Aquacize class where we meet Nora, one of the patients Nurse Annie passed to Mary earlier, and leading to the long stretch of beach Nora has chosen as the setting for her final breath.
Nora: Edward was a scientist. He always used to tell me 'Energy is not created or destroyed. It just is.' I believe every bit of him is still around. Just in a different form.
Mary: That's beautiful.
Nora: It's true
It is probably the most idyllic passing imaginable (in direct contrast to Troy Dixon's passing in "Bloody Mary"). Everything goes exactly as planned, exactly as Nora wanted it, and exactly as Mary set out to provide for her.
Mary and Des get paid (Nora even "tips" them each five dollars like the grandmother she was) and they leave the beach feeling satisfied in their deed.
But the show's tension is in the situations that are not going according to plan. More precisely, and most dominantly, the whole Joel fiasco.
Having had spur-of-the-moment sex with the supposed client earlier, Dr. Mary seems more interested in seeking new treatments for his cancer than delivering end-of-life solutions now.
This doesn't sit well with either Des (who, ironically, initially encouraged her to save the poor man from leaving this existence with "blue balls") nor with Joel who we know is actually an undercover agent of sorts, looking to nail Mary for her euthanasic activities.
Knowing that Joel is playing a part, it was fascinating to see how deeply sucked in Mary was to his supposed plight. The conflict in her is palpable when he tears a strip off her for offering him "hope" in the form of new clinical trials.
When his partner, Frank, calls her pretending to be his doctor, he prods her guilt even more with a few choice phrases.
It's a credit to Dhavernas' performance that despite Mary's fallible nature, she's still believable as a smart and compassionate medical professional.
Her life is full of complications beyond her choice of moonlighting activities – the mooching ex, the confused kids, the whole cat cover-up – and yet, she's a doctor I wouldn't hesitate to recommend.
I might question her choice in men... but that's not what I see my doctor for, now is it?
Mary: Hey, Des, never get married.
Des: You're the only woman I want in my life permanently. Which is why I keep rejecting your sexual advances
There's a lot of backstory revealed in "The River Styx" but the writers manage to keep it subtle.
Mary's motivation for providing euthanasia is hinted at. Des no longer has a medical license. Joel and Frank are having their strings pulled by a judge whose son may have sought out Mary's services.
What this episode blew out of the water was the Yvonne-Charlie storyline. Suffering from advanced ALS, Yvonne wants to end her life on her own terms and her fifteen-year-old son, Charlie, understands and supports his mother's decision.
Their situation is so painful that even the usually cool and distant Nurse Annie advocates for Mary to consider this an urgent case.
Mary: So you DO have feelings.
Annie: Buried somewhere deep down. Yeah.
Again, this show really digs deep when things go wrong. When Des has to tell Charlie they need to postpone his mother's death,
Charlie gets desperate and pulls a gun on him. Not realizing it's actually loaded, he grazes Des in the shoulder with a shot. Not a serious wound but it's enough to convince Mary they need to do the deed immediately after all.
Charlie: Does it hurt?
Des: No, it feels lovely.
Charlie: Seriously, I didn't mean to...
Des: ...shoot me?? Yeah, funny that, yet here we are. There's probably a lesson about guns embedded in all of this, eh, Charlie?
Mary had every right to freak out at this point. She had just figured out that Joel was a cop, trying to get her to describe her method of assisting suicide out loud.
She had dumped all her pento down a sewer drain. Her partner had just been shot. And now, in order to get more pento for Yvonne, she has to meet with an actual drug-dealer.
Grady is by far the most lethal-feeling individual introduced so far.
And we take a moment to appreciate that in an episode where Joel procures a gun to make it look like he's going to shoot himself and Charlie waves a gun around, Grady is basically armed with bunny ears and a Polaroid camera? And still comes across as the bad-ass.
Yvonne's final moments are just as evocative as Nora's from the opening of this episode but on an emotionally-wrenching level. Where Nora was obviously a physically active and vibrant individual right up the moment she toasted the sky with her pento cocktail, Yvonne's very breathing was labored and painful.
In preparing the pento for Yvonne, Mary has to point out to Des that Yvonne can't even swallow anymore and therefore, he gets his wish because the pento will have to be administered by injection.
Charlie is by his mother's side for everything – playing her favorite song on the stereo, holding her hand, and looking straight into her eyes as she draws her last breath and the lines of agony on her face finally smooth away. The love it takes to let his mother go is apparent in his tears.
Charlie: I want it to be peaceful
Mary: It will be. Like slipping into a dream at the end of a long day.
The dark humor of the series comes back in force while Mary is patching Des up.
He is coming up with advertising slogans for their future legitimate end-of-life enterprise (I think my favorite was "The spa you'll never want to leave. And you won't").
Then Mary realizes that her cat, whom she'd stashed at Des' when she made up a fake cancer diagnosis for her daughters, had probably fallen out the window and actually died.
Des: Aging baby boomers are going to want to die in the same manner in which they lived - bourgeois comfort. Now, the Swiss they know that. That's why death tourism is such a massive business over there.
Des: And we should be starting to buy up property, getting ready to go legit. I'm serious. I'm having an entrepreneurial seizure here. Let's be a start-up for shutting down. The spa you'll never want to leave. And you won't. If you're travelling the River Styx, why not take a yacht?
The show strings the episodes together with a couple of hit-and-miss elements. Troy Dixon's widow is very obviously going to become a player in the plot, having found the end-of-life consultant pamphlet previously and then making contact with Mary at the end of this episode.
Meanwhile, in the sub-plot I have the least time for so far, Mary's daughter, Jess, and anything-for-a-high bestie, Naomi, continue to make bad choices. Teenagers. Go figure.
That Polaroid Grady snapped is bound to reappear. How do you think that'll play out?
Now that Joel is actually Ben, where does that leave Mary's feelings for him?
Anyone think that Casper might've actually survived the fall?
There's a lot going on in these episodes. Don't miss out on the details, watch Mary Kills People online.
Diana Keng is a staff writer for TV Fanatic. Follow her on Twitter.