Reunion proved itself to be every bit the "epic revenge thriller" BBC One promised it would be, and the bilingual series came to a devastating finale - here's the ending explained.

Viewers were introduced to deaf man Daniel Brennan, a man released from prison after serving 10 years for murdering his good friend Ray.

However, it soon became apparent Daniel was determined to right his wrongs, while unravelling the truth behind the events that led him to prison. Although he did not seem to protest his innocence, it soon became abundantly clear that Daniel was seeking revenge - but for what?

Here's a recap of the Reunion ending, as we explain who really killed Ray, how and why, and news on a possible series 2.

***Warning: spoilers from the Reunion ending ahead***

Reunion ending explained

At the end of BBC drama Reunion, viewers finally discovered the truth behind the death of Christine's husband Ray. A tale of historic sexual abuse, police corruption and, above all, human relationships, the four-part series ended on a bittersweet note.

As well as giving Daniel Brennan the closure he so desperately needed, viewers also discovered how Ray really died, and what happened at Hawthorne Park school.

Daniel and Ray were old school friends from the boarding school, where tragically many of the boys were sexually abused by the headmaster Jim Monroe. Although they had all buried their memories in order to survive life after school, "it all came flooding back" for Daniel when teacher Ray took on the role of headmaster years later.

He later admitted: "Ray's new job changed everything." While Ray wanted "to make it right" by going back to the school and helping the current intake of children, Daniel wanted to track Jim Monroe down and confront him.

Talking to fellow schoolboy Sean, who had also been abused by Jim, Daniel explained: "I tried to stop it all those years ago, but I couldn't. I had to stop him. I tried to burn the school to the ground. It was the only way to save us from him - from Monroe."

He added: "Monroe was clever. He made you feel so special, so loved. Then he kept coming back for more."

He went on to explain that because he was subsequently expelled, he was "finally safe and free".

Who really killed Ray, how and why?

In the Reunion ending, we discovered that Daniel HAD killed his friend Ray. He stabbed him with a hunting knife during a heated conversation about their past outside a pub.

While Daniel was intent on getting revenge on their old headmaster Jim Monroe, Ray said: "It's all in the past. I'm over it."

We discovered that Daniel had a hunting knife on him, which he described as the "same as Monroe's when he used to take us on those camping trips".

During an increasingly angry exchange, Ray admitted he had agreed to be head boy at Hawthorne Park in order to 'help' Jim Monroe abuse boys. That way, Ray avoided being targeted himself.

Devastated to learn the truth, Daniel stabbed Ray in fury. However, he swore never to tell Ray's wife Christine or daughter Miri his role in the abuse. Although, of course, Ray was a victim of grooming just like the other pupils at the school.

Reunion ending recap: What happened to Jim Monroe?

At the end of Reunion episode 4, Daniel tracked his former head Jim Monroe down to an isolated house.

After former Hawthorne Park pupil Sean took his own life, he left a letter to Monroe telling him he was culpable for the abuse. Of course, this also gave Daniel the address he'd been desperately looking for.

With his daughter Carly by his side, Daniel confronted Monroe who initially pretended not to know him - or to understand British Sign Language.

Between them, with one signing and the other interpreting, they read Sean's letter to Monroe. However, the former Head showed no remorse.

Daniel eventually realised nothing could come of their meeting. He said: "I wanted to hurt you for so long, but it won't change anything."

Although Carly had different ideas. Furious after finally learning the truth about her dad's historic abuse, she grabbed her dad's gun and shot at Monroe. She missed, but it did force the paedophile to whimper an apology. While Carly threatened to report Jim Monroe to the police and ruin the rest of his life, Daniel told her it was "over". We can only assume that this meant Daniel did not plan to take further action against his abuser.

How was Christine's boyfriend Stephen connected to the case?

Viewers knew from episode 1 that there was something fishy about Christine's boyfriend Stephen. We soon found out that the former cop was the officer who got the confession out of Daniel all those years ago. Crucially, Daniel refused legal counsel, knowing that he had killed Ray.

However, Stephen made sure Daniel was accused of pre-meditated murder even though it wasn't. It was blatant coercion. In a bid to further his career, Stephen engineered it for Daniel to get the full sentence, despite there being extenuating circumstances.

He later hid the truth from girlfriend Christine.

Did Daniel go back to jail?

In the closing minutes of the Reunion finale, Daniel and Carly walked away from Jim Monroe's house only to find themselves surrounded by police.

Of course, Daniel - intent on revenge and fully prepared to return to prison because of it - had not checked in with his parole officer.

He had also been reported for the altercation at the party in which Miri was accidentally hurt.

At the end of Reunion episode 6, armed police circled Daniel and it didn't look good. Not only was he in violation of his parole terms, he was also carrying a rather big gun. In an attempt to protect her dad, Carly put herself between the police and Daniel giving him a bone-crushing hug.

Reader, we cried. It was a fitting - albeit unfair - ending to an emotional journey. The scenes between Daniel Brennan and his estranged daughter were incredibly moving throughout as they navigated their new relationship. Although it looked like Daniel was heading straight back to jail, he had his daughter to visit him and wait for his release.

What else happened at the end of Reunion?

• Carly revealed she was in debt as a result of her mum's funeral. She had borrowed money to be able to pay for a service and a gravestone. The loan sharks she borrowed off were also the reason she'd moved away from her grandparents' house - she didn't want to put them in danger after she struggled to make the payments.
• Christine dumped Stephen. When she confronted him about his part in Daniel's imprisonment, he insisted he'd changed since then. He said he wasn't in a good place at that time - his marriage was failing and his job was on the line. Stephen also swore that he had no idea who Christine was until he want to her house for the first time and saw a photo of Ray on the fridge. Still, she kicked him to the kerb.
• Thanks to Daniel Brennan's last promise to Ray as he lay dying, Christine and Miri did not discover that their dad had 'helped' Jim Monroe cover up his abuse. Carrying the guilt for his whole life was enough of a punishment.

Is there a Reunion series 2?

BBC One has not yet confirmed if there'll be a series 2 of Reunion. As it stands, the series came to a satisfactory ending.

However, that's not to say that we wouldn't love to see the characters again. There'd still be plenty to explore in a possible series 2.

A second run could follow the growing relationship between Carly and her dad, as well as reconnect with Christine and Miri as they make their way through life without Ray.

Of course, Jim Monroe was still alive and free at the end of the series, too...

Read more: Five 'awful' flaws viewers have criticised in the BBC One crime drama This City is Ours

Reunion is available to watch on BBC iPlayer.