8 big questions we have after last night's episode of The Replacement

Did Paula murder Kay? Who is Georgia? Can Vicky McClure turn water to ice with her eyes?

Ooh it's getting creepy, isn't it? Last week's opening episode of BBC One's The Replacement laid the foundations of the psychological thriller with deliberate care, before dropping a big old murder clanger into the mix in the last five minutes.

In Tuesday night's episode two the tension between our two main characters - Glasgow architect Ellen (Morven Christie) and her maternity cover Paula (Vicky McClure) - was cranked up a notch, with new mother Ellen pulling the full Poirot on Paula to establish whether she did, in fact, murder Kay.

Here are some key questions we want answered in next week's finale:

Did Paula murder Kay?

We discover Kay apparently believed David was having an affair, which is why she committed suicide. Ellen doesn't buy it. The suicide conclusion by the police does feel a little extreme and, given what we saw of Kay in episode one, a little out of character. Would she not confront David, who denies the affair to Ellen outright? But then if Paula did murder her then what possible motive would she have? 'I finally know what's been going on around here' she says on the phone to Ellen minutes before her death.

Was Paula really at home on the night Kay died, as she claims she was?

It's pretty clear Paula's husband Kieran (Navin Chowdhry) is hiding something. Did you see the awkward look he gave when Ellen asked whether he and Paula were really at home with their daughter on the night of the suicide/murder, suggesting Paula doesn't actually have an alibi?

What's the deal with Caris?

Ellen thinks the clue to where Paula was on the night of Kay's death could lie with her daughter Caris, who she claims she was at home with. When she gets in touch with her through social media suggesting a meeting (bit creepy of you, Ellen) we see it's Paula answering the message (dun dun DUUUN!) which suggests she's fabricated (even more creepy of you, Paula). But then Paula brings Caris in to meet Ellen while she's at work. Which means she exists! Or DOES it? It's odd how weird and cagey Caris gets with Ellen when she offers to give her a tour of the office. Is she actually Paula's daughter or a paid actress? When Ellen asks seemingly innocuous questions about Caris at dinner later that week Paula also seems very reluctant to answer them. Another dark possibility: the real Caris could be dead.

Who is Georgia and why does she freak out on Ellen?

After rifling in Kay's purse, Ellen tracks down a woman named Georgia who Kay called about a meeting before she died. Georgia works for another architecture firm which Paula did some work for a few years ago. But when Paula discovers Ellen is going to meet her we see Paula making a hasty phone call. When Ellen arrives (leaving her baby in the car) Georgia storms out and tells Ellen to leave her alone. Which begs the question, does Georgia have information about Paula which Paula wants to hide? Perhaps Paula pulled the same in-work sabotage on Georgia that she appears to have done on Ellen, which is why she wants to be left alone now. This could also mean Paula is blackmailing Georgia to stay quiet.

Is the baby-in-the-car picture the strongest clue about Paula's real character?

We've been lobbed some pretty major hints that Paula is underhand, but sending the picture of Ellen's baby in the car - which leads to an intervention from social services - is solid proof that she'll go to extreme lengths to screw her over.

What can we learn from the most awkward dinner of all time?

Paula's husband Kieran isn't going to win an Oscar for subtlety any time soon. After the foursome dinner party at the end of the episode he pointedly asks Ellen's husband Ian (a psychiatrist) about 'a friend' (cough cough) whose wife 'has a problem accepting reality.' Wow - who could he POSSIBLY be talking about?! If Paula really has a problem accepting reality then much of what we believe to be true (mainly this mysterious disappearing daughter) could be false.

Is Ellen's baby going to be taken away by social services?

After being caught leaving Lea in a locked car (and with a history of mental illness) Ellen is potentially one strike away from being separated from her baby. Something tells us her dogged pursuit of Paula could land her in far more trouble than she's already in. In any case, her husband Ian already appears to be at the end of his tether.

What is going on with David?

A clearly grief-striken David gets angry that Ellen wants to do more digging on Paula. But it also throws up the possibility that he knows more about Kay's death than he's letting on. Ellen also finds Paula's lipstick in the bathroom at his house. Does this suggest he was actually having an affair with her or is it a red herring?

Speaking of the baby, how cute is the baby?

VERY cute.

Also, how nice are the houses in Glasgow?

Lovely spacious living rooms, modern kitchen units, tasteful furniture, fancy floating staircases. Just a shame about all the murderous architects.

Could Vicky McClure freeze water with her eyes?

Quite possibly.