There's a big plot hole in The Sinner's final episode. We don't know how we missed it.

* Warning: This post contains HUUUUUGE spoilers for The Sinner season one. They’re huge.

If you haven’t heard of The Sinner – the new Netflix crime series people are bingeing in one sitting – start coughing because you’re going to need to leave work sick, like, NOW.

The ‘why-dunnit’ psychological thriller which follows young mum Cora Tanetti (played by Jessica Biel) after she murders a stranger at a family day at the beach is pretty much responsible for the bum-shaped dents in couches around the world that form when one watches TV for eight hours straight – it’s that good.

But as the saying goes, love is blind. It’s with this in mind we regret to inform you of the glaringly obvious plot hole in The Sinner season one episode eight that we all missed.

‘Nah, not me. I’m obsessed with this show,’ you say as you vacuum the remnants of the multiple boxes of BBQ shapes consumed during that eight-hour Netflix marathon.

We were too. Which is why finding out the finale is kind of a lie hurts so bad.

But in our blind admiration of the show that gripped us and didn’t let go, we missed the episode eight story line, as pointed out by Digital Spy, that just doesn’t make any sense.

*P.S. If you missed the spoiler alert up top ^^^ NOW would be time to leave.*

After seven episodes of slowly untangling the mystery of the secret in Cora’s past that made her a killer, episode eight provides some long-awaited answers.

We find out that all of Cora’s memories of Maddie (Danielle Burgess) had nothing to do with Maddie – they were actually memories of her chronically sick sister, Phoebe.

(Image: Netflix)

It was Phoebe who Cora took to the bar, and then a party that night.

It was Phoebe who was accidentally killed by Frankie, the man Cora abruptly murdered five years later at the beach.

We also discover Frankie's father is the reason Cora lost those two months of her life. After burying Phoebe's body, Frankie's father plans to kill Cora to cover up his son's actions, but instead decides to hold her hostage in a room and inject her with heroin for two months until she can no longer remember what happened.

After those two months, Cora's parents find her getting clean in rehab, where she was dropped off by Frankie's father - NOT in Florida where they assumed she and her sister has run away to on Phoebe's 19th birthday.

Which is great and all, but...

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If Cora wasn't in Florida all along, why the flippin' heck does no one wonder where Phoebe is?!

Upon finding out they didn't move to Florida like they had thought, why do the girls' parents not ask Cora where her sister is? The sister who (FYI) has a heart condition AND leukaemia, and has been spending her entire life practically housebound being doted on by her mother.

We'd like to think our parents would be out scouring the forests and riverbeds if we had been missing for two months, sticking flyers with our faces on them to every toddem pole and notice board.

So where were Phoebe's flyers? Or a missing person's report, which would be even more important consider Cora has no memory of her sister's death or those two months.

And what about the doctors and specialists? Did they not wonder why their patient didn't rock up for one, or any of her regularly scheduled appointments?

Add in the fact Cora's parents told her Phoebe in fact had passed away during those two months, and pretty much nothing makes sense in the world.

Here's hoping Netflix figure this out and deliver us some answers in a second season.