Still Waters: Every clue that led to the real killer in the latest thriller show

Still Waters kicks off like a typical slow-burn Welsh drama, but a lot is simmering under the surface.

If you pay attention, you will spot a mountain of missed clues, old secrets, and family wounds. Everything builds to the show’s wildest reveal: Llyr Owen didn’t die in some protest gone wrong. His sister, Megan, killed him.

The final episode of Still Waters drops that bombshell out of nowhere, but if you look back, the signs are there. Some are tiny and hit you in the gut; others just don’t add up logically. Piece them together, and it’s Megan all along, even before the truth comes out.

Here’s every hint that pointed to the real killer, pulled straight from the series’ events, the tense flashbacks, people’s stories, and the little patterns that show up if you are really watching.

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Tracing every clue that led to the real killer in Still Waters

The longstanding Owen family rift (1966)

The tragedy in Still Waters started a long time ago. Back in 1966, Bryn Owen, Megan, and Llyr’s uncle tried to stop the Nantwen Reservoir from being built. He lost that fight, and it cost him everything. Alan, Bryn’s brother and the kids’ father, ended up working for the same project because he had no other way to make ends meet.

That tore the family apart. Alan never really got over it, and the fallout shaped his kids in completely different ways. Llyr looked up to Bryn and picked up his activist streak.

Megan, however, blamed Bryn and Llyr too, for everything that happened to their dad. That rift says it all. Megan held onto that resentment, way deeper than she ever let anyone see.

Throughout Still Waters, Megan tenses up every time someone brings up the family’s past. At first, it seems like she is just sad or haunted, but really, she is holding onto anger she has never let out. She has a quiet grudge against Bryn for always needing to be an activist. She is frustrated that Llyr decided to copy Bryn’s path, too. And deep down, she blames all this rebellious energy for tearing their family apart.

It doesn’t jump out at you, but that resentment matters. It plants the seed for why she does what she does, even before the murder comes to light.

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The Eve–Rhys–Llyr triangle as a trigger

Eve Davies gets tangled up with both Rhys and Llyr, and things between the cousins get heated. But here is the real clue: it’s all about how Megan reacts.

When Robert Davies, Eve’s dad, bursts into Alan’s place and threatens to kill Llyr, Megan freaks out. Not because she is worried about her brother’s safety, but because she is terrified this will wreck her family’s reputation, which is already hanging by a thread.

She doesn’t rush to protect Llyr. Instead, she lets her fear and frustration take over. In that moment, it’s pretty clear: Megan doesn’t see Llyr as someone to defend. She sees him as a problem, someone who keeps putting the family at risk.

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Megan’s decision to go after Llyr

When Megan finds the map in Llyr’s room, she instantly decides he must be at the reservoir. This whole scene in Still Waters raises eyebrows for a few reasons:

First, she acts on impulse. Instead of calling Gareth, her partner, who is a cop, by the way, she just heads out on her own.

Then there’s how she gets to the reservoir. The show doesn’t bother to explain if she has a car, how she travels, or why nobody notices her. Somehow, she shows up at the exact spot, right when Llyr’s there too. It’s hard to buy, unless she was obsessively tracking him in the first place.

And then, there’s their confrontation. When Llyr tells her to leave and lifts his hand, Megan loses it. It’s not just a random outburst; it’s anger that’s been building up for years.

This is the moment everything shifts in Still Waters. It’s the first big clue that Megan has both motive and emotional instability right then and there.

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The bolt cutter clue

This is the key piece of evidence. The bolt cutters were Bryn’s, but Rhys’s fingerprints turned up on them.

Here’s why that matters: Megan used those cutters to kill Llyr. Then she just left them there. Those fingerprints are the only reason Rhys ended up convicted.

It doesn’t just suggest who is guilty. It shows Megan was either so rattled she forgot to cover her tracks, or just too scared to think clearly. Whatever the case, leaving the weapon behind really puts the spotlight on her.

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Megan’s silence

The biggest clue in Still Waters was right there the whole time: after 1995, Megan’s life just kind of folds in on itself. Look at what happens. She dodges any talk about Llyr. She pulls away from her family. Gareth becomes her lifeline. She gets way too protective of Hari, her son. You see her acting out of guilt; she withdraws, gets anxious, and avoids people.

These are classic signs of someone weighed down by a secret, and Megan shows them again and again.

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Gareth’s behavior around the case

Gareth wasn’t there when the murder happened, but his actions still raise eyebrows. He shows up after the killing but before the explosion. He follows protocol and gets out of there when the blast hits, but he never talks about what he saw, not even with Megan.

Now, whenever someone brings up the 1995 case, he gets edgy. It’s like he knows more than he lets on. That makes Gareth a solid hint that Megan is involved, even if he is not the main clue.

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Hari’s disappearance and Megan’s collapse

In the current timeline of Still Waters, Hari’s vanishing isn’t just a plot point; it’s the price Megan pays for what she has been hiding.

When Megan melts down and insists Hari will die unless she confesses, that’s the mask slipping. You can’t really explain a reaction like that unless she has been eaten up by guilt for a long time.

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The confession scene: The final link

It’s not exactly a clue. It is more like the moment when all the clues snap together in Still Waters. Megan asks Caryl to meet at her old family house. That place isn’t just a location; it’s where everything started for her. You can see how much it means, and how heavy it feels.

She has been carrying this confession around for years, wanting to let it out but never managing to do it. Her guilt just seeped into every part of her life, weighing her down. Then her son disappears, and that’s it. She can’t hold it in anymore. When she finally speaks, suddenly everything makes sense. The whole story locks into place.

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Still Waters is a tragedy in slow motion

Megan Owen didn’t kill Llyr just because of one argument. The truth runs deeper.

Her family’s messed-up history chipped away at her for years. To her, Llyr became a living reminder of everything that wrecked their lives. When it finally happened, she snapped. Decades of bitterness boiled over, and in that split second, she lost control.

Afterwards, panic kicked in, along with guilt. Instead of facing what she had done, she ran, and Rhys got blamed.

Look at the trail: the old Owen feud, Megan’s emotional unraveling, the bolt cutter prints, her thirty years of silence. All of it shouts her name long before the ending of Still Waters spells it out.

Still Waters explores old wounds that never heal, guilt that eats you alive, and how silence can destroy everything.