'Law & Order: SVU' Shocking Pregnancy Twist Surprises Fans

Thursday's new Law & Order: SVU left fans picking their jaws up off the floor courtesy of a twist that also leaves the SVU crew doing something similar. We not only start with a showdown between a daughter and her stepfather, we later get a murder that spins out of that fight, a mysterious pregnancy, and a wild courtroom revelation that we've come to expect from Dick Wolf's record-setting series.

The episode opens with 13-year-old Mackenzie (Eowyn Young) having a fight with her stepfather, played by Derek Cecil, where she ends up cutting him. The police are called by a neighbor shortly after and Mackenzie is taken in for a hospital check. Olivia Benson (Mariska Hargitay) and Dominick Carisi (Peter Scanavino) from arrive to check out the domestic scuffle at the hospital but quickly learn about the pregnancy.

The news shakes her stepfather and the detectives take them to the station to lob a few questions their way. Her stepfather, Garrett Howard, is confused by his stepdaughter's admission and pregnancy. Mackenzie, on the other hand, was happy to discuss her baby but not the details of how she got to be that way. Benson and Amanda Rollins (Kelli Giddish) handle the interview with the teen but can't get too deep just yet. All she mentions is that she met her baby's alleged father at Whole Foods and he drove a blue BMW. They don't have much more to go on, but once Carisi and the SVU "computer geeks" get involved and tap her social media, they're led to Mackenzie's school and a pair of male students.

The two boys pictures smooching McKenzie is a dead end with them, but it does point them at Quentin Dreyfus (JD Taylor), the school's drama teacher and the owner of a blue BMW -- connecting him to Mackenzie's story at the police station. Carisi and Rollins ask him to come with them, threatening an arrest if he doesn't choose to come willingly.

Dreyfus is willing to give DNA and quick to claim his innocence. Howard, not so much. He holds tight to Mackenzie's claims that she was not raped and that she wants to keep the baby. It's a roadblock and forces Benson to chat with Peter Stone (Peter Winchester) in order to get a court order for Mackenzie's DNA.

This leads to a morals discussion between Benson and Rollins over the privacy of a 13-year-old -- including some drama about Benson's advice on "regret" to Rollins from earlier episodes. This gets cut short when Mackenzie arrives at the station with a rude taxi driver to inform the detectives her father went after Dreyfus once she admitted to him that the teacher was her baby's father.

They arrive a bit too late, with Howard sitting over Dreyfus' dead body, blood on his face and murder weapon in his hands.

Howard is arrested for the murder, but the twists are far from over in the episode. After Howard discusses why he committed the murder and aims for a plea deal, a surprise comes to DA Stone's office. While building the case against the stepfather, Stone is visited by a friend of Dreyfus named John Woodward (Richard Prioleau). He reveals that he and Dreyfus were going to get married, were in a relationship and that Mackenzie is lying about him being the father of the child. He even reveals that the bowling trophy used as the murder weapon came from an LGBT league.

Stone calls Benson for help and she tracks down Mackenzie to press her about the real father of her baby, and why she is lying about Dreyfus. Benson presses Mackenzie about her stepfather's possible involvement in the pregnancy, but she drops the bombshell that he wasn't aware of the pregnancy. After meeting with Stone, Benson and the DA agree that Mackenzie's take on the events would give her stepfather a defense for the murder -- even if she's lying about the father of her child.

None of this prepares the DA or the detectives for the twist that comes in the courtroom. When calling Mackenzie to the stand to testify, the attorney for the defense reveals that the 13-year-old is legally married to her stepfather. He presents the marriage license for Stone and the judge, leaving everybody -- including -- a little stunned.

So not only is Garrett his stepdaughter's husband, but he is also the father of the child she is carrying. The detectives look into the marriage certificate the find that it is authentic, leaving them scratching for options.

They reach out to Mackenzie's aunt, played by Pamela Mitchell, and then end up tracking down her father to find that he was paid by Howard in order to gain consent for the marriage to take place.

Mackenzie's father goes to court with Stone to try and remove his consent for the marriage, leading to the teen finally taking the stand and defending her relationship with Howard. The judge is forced to uphold the marriage and Missouri's laws, labeling the marriage as valid and blocking the original trial from moving forward with the teen as a witness.

Things seem grim for Benson, Stone, and the prosecution's case. Their hands are legally tied and Mackenzie cannot testify against her husband. Luckily, Benson has an idea that preys upon the idea that Mackenzie's husband will do whatever he can to protect her.

Stone calls Mackenzie and Howard for a meeting ahead of the trial, informing them that they were going to drop the charges against her stepfather and charge her instead. This leads to a dramatic showdown that sees Howard reveal why he killed Dreyfus, why Mackenzie lied and eventually forces their attorney to agree to a plea bargain. Howard is going away for nearly 20 years.

After the dust settles, we get the perfect Benson moment where she meets Mackenzie on the street and gets her to realize what she's gone through, and how being a mother will bring her more love than her relationship with her stepfather ever could've. They close out with a tearful hug and another SVU case is wrapped up.

Law & Order: SVU airs Thursdays on NBC at 10 p.m. ET.