Who keeps calling Clay? The 13 Reasons Why mystery revealed

Clay and his friends framed Monty for Bryce's murder despite Alex committing the crime and the only person who suspects a thing is Winston, Monty's sort of boyfriend.

From the off it's clear Clay is struggling. In the first episode he's still haunted by the ghost of Monty as he hallucinates throughout his school day and dreams of him at night.

In the second episode Clay gets a phone call from Monty's phone, but the voice is distorted.

Monty is dead, there's no sudden resurrection here, so then who is calling Clay?

Who is calling Clay in 13 Reasons Why?

Clay first gets a call from Monty's phone number as he fills in his college application - he tries to FaceTime twice. When he gets a call the next day at school he reveals that the caller has been pestering him, that first evening he rings 15 times.

"Monty was framed," the caller says, "You framed him." The caller has images too and sends them on.

By episode three, the calling has really ramped up. Clay is constantly taking calls, with the caller showing he can see Clay - he's at the school.

First Clay thinks it's Winston that is pranking him because he was near him when he picked up. He asks the caller if he's Winston but he angrily replies: "Who the f**k is Winston? Don't you recognise the number?" It's Monty's so of course Clay does.

The calls don't stop and Clay starts to follow the instructions or he risks the caller revealing the truth. It's essentially blackmail.

The voice tells Clay he has to start a fight at school so Clay turns to Zach for help asking him to hit him and that he won't fight back. While Zach refuses to start with he reacts when Clay goads him.

Eventually Clay tells Ani about the calls and she tells him to ignore them. Nothing has changed, people think Monty killed Bryce.

The caller takes action, punishing Clay for telling Ani about the calls. The next calls sees him checking bins for Monty's phone after he's told he can find it there - he finds a burner phone.

The calls carry on to the Valentine's Day dance where the caller lets him know he's watching.

Clay is told to leave the dance and go to the locker room. As he enters he sees blood and a knife on the ground - while it's most likely the same paint from the message on the doors (giving away that Monty was framed) it unsettles Clay who has a melt down.

He grabs the knife and heads to the football field where he starts to see Monty again. Clay tries to save Monty, but realises it's pointless as he cries saying he's sorry.

Who is the prank caller?

Diego, the footballer who likes Jessica, and the team run on to the field as Clay clocks that it was a fake bloody dummy on the field.

All the team have phones and they reveal they used software to ring Clay from Monty's phone. Diego is surprised to see how Clay has reacted to the prank and he starts to wonder what he's hiding.

While Diego seemed nice, he now warns Clay: "We're on to you."

The prank was most likely just the team getting back at Clay for the fight he started at the start of the season. When the team made jerseys to pay tribute to Monty it triggered Clay who lashed out and fought them in the cafeteria. Diego planned a prank, but was completely unaware of how close he was to the truth.

Now he's left wondering what's going on and time is running out for Clay...

If you have been affected by the issues raised in this article, contact Samaritans for free from any phone at any time of the day or night on 116 123Season four of 13 Reasons Why is now available on Netflix – check out our lists of the best TV shows on Netflix and the best movies on Netflix, or see what else is on with our TV Guide