Kate Beckett spent her first day as captain conducting a rogue mission in the "Castle" season premiere. Now, a group of mercenaries has tracked her down and is about to breach her hideout.

In a sneak peek from episode "XX," Beckett (Stana Katic) and her pal Vikram Singh (Sunkrish Bala) need to make a quick getaway. As they come down a back staircase, two soldiers cut off their path until a woman in the shadows guns them down.

It's a lucky save, but who is this woman with the excellent marksmanship?

"You can call me Rita. I'm Castle's stepmom."

Yes, Castle's father apparently married another super spy who is also willing do anything to keep the family safe. Whether Beckett shares this little family secret with her husband remains to be seen since she's harboring a few other secrets from him at the moment.

When Beckett and Castle (Nathan Fillion) finally reunite, she promises to not keep any more secrets. But he's still worried that she may go down the rabbit hole on this new case as she did with her mother's murder.

Watch how it all unfolds when "Castle" returns on Monday, Sept. 28 at 10 p.m. on ABC.