Military veteran Michael VanZandt disappears one night in Hermosa Beach, Calif.; police suspect a group of strangers may be involved, while VanZandt's loved ones are haunted by suspicions about his thrill seeking make-up.

Nancy Moyer isn’t home when her kids come back from visiting their dad. Police look into her background, and find a more complicated life than anyone knows. But when a random murder occurs nearby, the question becomes could the cases be connected?

Stephanie Crane, aged 9, leaves a local bowling alley but never arrives home; years later, authorities hope that advances in evidence testing may finally solve the mystery.

Ali Lowizter, 16, vanishes after getting off her school bus; the investigation stalls for two years until a tip comes in claiming Lowizter could have been trafficked, leading to a SWAT team raid on a house of prostitution.

While on a Caribbean cruise, 23-year-old Amy Lynn Bradley vanishes from her family's cabin and is never seen again; over a decades-long struggle, her family embarks on countless grueling searches, stopping at nothing to find their beloved Amy.

Stephanie Crane, aged 9, walks home from the local bowling alley, but never arrives. Early leads go nowhere. For years authorities don't find her or make an arrest. Now, they hope that advances in evidence testing may finally solve the mystery.

Holly Cantrell is seen on security video leaving the hospital where she works, but she never arrives home; while investigating Cantrell's disappearance, police learn she has been keeping secrets.

Logan Schiendelman vanishes, and authorities find his car abandoned; multiple tips claim seeing Logan, but searches turn up nothing; with no evidence of foul play, questions surface and police are forced to examine his family's controversial past.

Nineteen-year-old college sophomore Martin Roberts is a popular fraternity brother, then he goes missing, leaving behind a cryptic note; two years later, Roberts' family remains desperate to know what happened to him.

In Greensboro, N.C., 19-year-old Tyarra Williams vanishes from the parking lot of her apartment complex; after receiving tips that Williams may have fallen prey to human trafficking, her grandfather embarks on a cross-country search for answers.

Thirteen-year-old Tabitha Tuders vanishes while walking to her bus stop in Nashville, Tenn.; police think she's a runaway, but there are disturbing circumstances surrounding her disappearance, leaving her family desperate to find the truth.

When 70-year-old retired firefighter Michael Chambers goes missing, a bloody crime scene in his garage indicates foul play; then, authorities begin to believe that the crime scene may have been staged.

Ashley Summers is a fun-loving 14-year-old. When she vanishes on July 4th, her family is at a loss. The mystery deepens when the FBI connects her case to two other young women missing from her neighborhood. Ten years later, there's still no answer.