Stiles Teen Wolf "Teen Wolf" Season 4 episode 7 put Stiles in the way of a new assassin. Find out who in the recap below. Photo: MTV

“Teen Wolf” Season 4 finally gave Stiles a girlfriend, but it seems that he might not be together with Malia for much longer. Find out how a killer virus helped cause a rift between the two in Season 4 episode 7, titled "Weaponized."

The episode first introduces audiences to The Chemist, a new assassin who kills a random wolf by poisoning him. As it turns out, he’s a proctor for the PSAT with Mrs. Martin.

Before the test, Scott wants to give the duffel bag full of money back to Derek. Stiles argues that it’s half Peter’s. Stiles is clearly torn about what to do because he knows that money could help both of their families. Malia cuts them off when she comes by to tell them that she and Derek found Satomi’s pack dead, and all three have to head to school for the PSATs.

While taking the PSAT, Malia panics, but another student actually passes out. Mrs. Martin finds a weird rash on her arm. She visits Coach’s office (where he was passed out) and finds a rash has taken over his whole back. She calls the Center for Disease Control (CDC) who come in and quarantine the school.

Braeden was shot in last week's episode, and Derek brings her to the ER. She tells Melissa and Derek that Satomi’s dead pack was infected by a virus. Satomi brings one of the infected pack members to Deaton in hopes of curing him.

Lydia already took the test, so she is at her lake house with Meredith’s belongings. She asks Meredith for help. She picks up a picture and realizes it was taken in the room she is standing in. Lydia seems to know that something bad has happened because she packs up everything and heads back to school where she tells the Sheriff that someone is going to die in there.

More are coming down with the sickness at Beacon Hills High. While in line for blood samples, Malia asks Kira if Scott and Stiles hide things from her. Kira gets nervous and thinks that Malia might be asking about her real father. Malia asks if Kira knows what’s under Scott’s bed. Kira suddenly gets even more nervous.

“I’ve never been under Scott’s bed or in it, only on it. With clothes.” Kira says a little too quickly.

Kira has much more to be worried about, though. She accidentally creates a spark and burns the CDC agent’s suit when she tries to take Kira’s blood.

Viewers soon learn that everyone has the virus. Scott is infected and can’t stop himself from turning into a wolf. Stiles brings Scott, Malia and Kira to the Hale vault to hide them from the new assassin. Only a Hale can open the vault, but Scott and Stiles say that anyone with claws can do it. They say that Scott can’t control his claws because of the virus, so Malia has to do it.

Malia tells the group that they need to be honest with her, and she tells them that she knows she is on the deadpool. She wants to know how much she is worth and Stiles tells her that $4 million is her price. He asks if she is okay.

“Yeah, Scott’s worth 25. Kira’s 6. They’ll take you guys out way before me,” Malia says.

They get out of the school and go into the Hale family vault. Scott and Stiles talk about how the money that was stolen from there would help their families. Both seem to be in danger of losing their homes.

Once Malia falls asleep, Scott argues that they need to tell her about Peter. Stiles thinks it will only cause more problems with Peter. He doesn’t know how Peter will react, and he remembers all the pain the older werewolf has caused.

At the hospital, Braeden asks why Derek is sticking around. “I’m protecting my investment. I’ve got a lot of money riding on you,” Derek says. It’s clear from the rare smile on his face that he actually cares about the mercenary.

Elsewhere in the hospital, Deaton brings Satomi’s pack member to Melissa at the hospital, but he dies before Melissa even gets him to a room. However that puts Derek and Satomi in the same room, finally. Satomi tells Derek that he reminds her of his mother Talia. Derek doesn’t remember Satomi, but he does remember the tea she used to bring to Talia.

Deaton realizes that the tea is why Satomi is not infected. It worked as a vaccine, and it could be an antidote. Luckily, the Hales kept some in their family vault.

Stiles has to leave the vault to keep adults from looking for them. When he is in Coach’s office, he realizes that the ink pad was used to get everyone sick. They were fingerprinted for the test. Coach was using the same ink pad to stamp approved permission slips. The Chemist discovers Stiles in Coaches office and threatens to kill him if he doesn’t say where Malia and Scott are. The assassin needs visual proof of their deaths for payment.

Agent McCall kills the Chemist while he has a gun to Stiles’ head. He tells Stiles to give Scott a message from Melissa that he doesn’t understand. He tells him to look for a jar on the shelf in the vault.

In the vault, Malia pulls a piece of paper out of the jacket Stiles left her with. It’s the deadpool with her name on it. However, she is blinded. Scott uses alpha vision to cut through the oncoming blindness. He sees the jar glowing and pushes it off the shelf. All three of them inhale it and are healed.

When Stiles comes into the vault, Malia is cured of the virus, but she has read the deadpool with her name on it. It lists her as Malia Hale. She knows that Stiles has been hiding her parentage from her.

"Teen Wolf" airs Mondays at 10 p.m. on MTV. Do you think Stiles and Malia will make it through this? Sound off in the comments section below.