By Kristen Johanson

PHILADELPHIA (CBS) — It’s a mystery that has haunted two Philadelphia families for more than a decade: their loved ones disappear after a night out on the town.

Sunday night, their case will be featured on a popular national TV show.

READ MORE: DA: Shooting At Park City Center Mall Results In Injuries, Mall Closure

It was Feburary 19th, 2005 – Richard Petrone and Danielle Imbo went out to a few bars on South Street, and never returned home.

Sunday night on Investigation Discovery, producers and authorities retrace their last steps.

The couples loved ones unite to find them.

READ MORE: Protestors Demand Full Investigation Into Fanta Bility's Shooting Death, Want Sharon Hill Officers Fired

“It’s difficult to relive, it’s difficult to talk about,” said Richard’s mother Marge Patrone, who was interviewed for the show. “One day he was here, happy, healthy, working and the next day, I never saw him again.”

She says she will do anything.

“I know somebody knows something. More than one person had to be in on this. So we are just hoping that one day they will hear this, and decide to come forward,” said Patrone.

MORE NEWS: Ben Simmons Practices With Sixers For First Time Since Returning To Team

The show, called “Disappeared,” airs at 9pm.