On Friday night, viewers who tune in to watch the new episode of NBC's "Dateline" will get a closer look at the deaths of Christina Karlsen and her son, Levi Karlson.

Christina met her former husband, Karl Karlsen, when he was stationed in the Air Force in North Dakota. After getting married and having children, the two decided to relocate to Seneca County, New York after he left the military in 1985. However, due to the lack of opportunities that he saw in the area, Karl continued to look for ways out.

At that time, Christina's father offered Karl a job in California, where he could work for his heating and air conditioning company.

"I told him, I said, 'You know, if you ever need a job, just come on out to California and you'll have a job,'" her father recalled to correspondent Andrea Canning, as seen in the preview below.

After the relocation, tragedy struck when a fire engulfed the small house that the family had moved into. The intense blaze, which took place on New Year's Day 1991, commanded local firefighters to immediately come to the location. When looking back on the events of that day, a firefighter who had been at the scene recalled that they could feel the heat and flames as they approached, but that they couldn't get close to home.

Ultimately, Christina's body was recovered after the fire was extinguished. However, Karl and the three children that the couple shared all made it out alive.

After Christina's death, Karl relocated yet again and began raising his children as a single father, until tragedy struck again. This time, a "freak accident" had claimed the life of Karl's son, Levi.

On Friday, viewers will get to take a closer look at the man attached to both deaths, Karl Karlsen, as the NBC true crime show examines the unusual circumstances.

This episode of "Dateline," called "The House on the Hill," will air Friday night at 9 p.m. EST on NBC.

"Dateline" key art is pictured. NBCUniversal