What's in the box? It's a mystery NCIS: Los Angeles fans and actor have spent the last four years puzzling over, and, unfortunately, it's one that will keep going just a little bit longer.

First introduced during season 4's "Red: Part One," Kensi's (Daniela Ruah) gift to Deeks (Eric Christian Olsen) is the unofficial fifth member of the OSP team, perpetually hanging out in the back of the bullpen. A veritable Russian nesting doll of boxes, the package has technically been opened, even if it was only to reveal a second, equally inscrutable box within it.

As season 8 begins, both Deeks and viewers alike will continue to ponder the contents. As of San Diego Comic-Con, Olsen was no closer to learning the truth than us.

"I don't know, I don't know," Olsen said, explaining that he has no idea what the writers have planned for the package. "It's a lot like life, that's what I've found out about television. You give me a movie and I know where it starts and I know where it ends. With television, I'm waiting to get the script and we shoot it two days later and I'm like, 'Oh! This happens?' So I am just as in the dark as everybody else is."

Those wishing to learn the truth will have to lobby series creator Shane Brennan for answers.

"The only person that knows what's in there is Shane Brennan, so I am as emotionally invested as everyone else," Olsen previously told Entertainment Weekly, joking that he would like to break in one night and find out the truth for himself.

When NCIS: LA ultimately goes off the air 20 years from now, we're half convinced the final shot will be of an abandoned office, empty except for a dusty and sun-bleached cardboard box.

Find out if season 8 will become a season of reveals when NCIS: LA returns to CBS on Oct. at 8 p.m. ET.

Tags: NCIS: LA NCIS: Los Angeles television CBS