It's time to blow Quantico's Mark Raymond mystery wide open.

Will (Jay Armstrong Johnson) stumbled upon Caleb (Graham Rogers) and his alter ego during "Answer," and the rocket scientist's sneaking around revealed two more major clues to the agent's shadowy side story.

It's clear the FBI's golden boy is still attempting to take down some sort of religious cult - weather it be scientology or a made up stand in - and he's somehow managed to wrap Samar (Marjan Neshat) and Shelby's (Johanna Braddy) $5 million dollars into his scheme. How is it all connected? Prepare to find out the truth as episode 15 and 16 unravel.

"I will say the Mark Raymond story becomes exceptionally clear and everything will be revealed in the next two episodes," executive producer Josh Safran told Entertainment Weekly.

In fact, viewers should expect a lot of the series' mysteries to come to a head as multiple plotlines converge in Sunday's "Turn."

"Episode 15 really is the culmination of several of our storylines. It involves an event at Quantico that changes everybody's trajectory forever," Safran teased. "I kind of think of that as the spot in the season where everything comes together and the place that everyone shoots off of from that episode will line them up tragically or not with where we find them in the future, in the beginning of the season."

You can rest assured that the events of the March 27 episode will have you biting your nails through both the past and future segments.

"A terror cell tries to infiltrate Quantico, forcing Miranda and Liam to pay a deadly price," ABC teased. "In the future, Alex continues to get instructions from the terrorist - only this time, it's Claire Haas' (played by Marcia Cross) life that hangs in the balance."

It certainly sounds like there is plenty of opportunity to Caleb's name to pop up in the future (we haven't seen him since the command center bombing), while all bets are off down at Quantico (see a preview below).

Catch Quantico Sundays at 10 p.m. ET on ABC.

Tags: Quantico television ABC