An elementary school teacher who destroyed her marriage by having sex with a 16-year-old boy inside a pick-up truck took a sweetheart plea deal that will put her behind bars for less than a year.

Mackenzie Naught, 25, was arrested at her home in Washington State in May after her husband, Garrett, uncovered her crime.

The teen, whose family is reportedly friends with the Naughts, told Garrett about the encounter after the horrified husband discovered messages between the two. 

Naught, who is a mother of one and worked as a first-grade teacher at St John-Endicott Cooperative Schools, initially denied having any physical contact with the boy, and instead accused her husband of infidelity.

She eventually confessed to having sex with the boy and pleaded guilty to first-degree sexual misconduct with a minor on Friday. 

As part of the deal, Naught now faces a possible punishment of 6 to 12 months in prison, according to the Whitman County Prosecutor's Office.

'The defendant's guilty plea represents an important step in holding her accountable for her actions and spares John Doe the burden of having to testify at trial,' Whitman County Senior Deputy Prosecutor Tessa Scholl said in a statement.

'Our office remains committed to supporting John Doe and his family throughout the remainder of the judicial process.'

She will also be required to register as a sex offender for 10 years, and a five-year protection order for the teen she abused is in place.

Naught was remanded to the Whitman County Jail until her sentencing, which is scheduled for August 28.

The Daily Mail contacted Naught's attorney for comment. 

Naught's victim, who is nine years younger than her, is enrolled at the high school where he husband works as an assistant track coach.

The teen told police he had been messaging the first-grade teacher and her husband on Snapchat, but when Garrett fell asleep, he and Naught continued messaging.

He said she was 'being flirty', tried to get him to meet her and that he 'felt weird about' her alleged overtures, according to a probable cause affidavit seen by the Daily Mail.

The boy eventually agreed and picked Naught up from her street at around 2.15am.  He told deputies that she asked him to take her to a 'little spot' where they could hang out, so he drove her to Harwood Hill, a nearby agricultural area and rural road, investigators say.

The pair had been talking for a while when Naught suddenly kissed him and started to touch his genitals over his pants, the court filing said.

He alleged that both his and Naught's pants came off after he moved from the driver's seat to the passenger seat, where she had been seated.

That's when Naught climbed on top of him and tried to perform a sex act on him, the affidavit said.

He claimed he 'felt weird' and was struggling to comply with Naught's sexual demands.

The pair then moved to the bed of his pickup truck, according to the affidavit. He lay down, and Naught continued to try to sexually abuse him, it is claimed.

Shortly after, the boy ended the alleged encounter, according to the court filing.

They then got back inside the truck, and he dropped Naught back near her home around 4am, he told deputies.

Naught eventually admitted to messaging the boy on Snapchat while intoxicated, meeting up with him and having sex in the truck.

She told police she was 'really sorry' and 'knew it was wrong' to have sex with the boy, the court filing said.

Naught also told police that there was 'a lot of infidelity' and 'anger' in her four-year marriage to Garrett, which has produced one son, the filing says.

Continuing to bare her soul, Naught claimed there was 'no trust' between the couple and that it was 'time for them to get divorced,' according to the court filing.