The cat's out of the bag on Grey's Anatomy.

And by "cat," we mean the romance between Meredith (Ellen Pompeo) and Riggs (Martin Henderson), which quite literally soared to new heights in the previous episode.

Thursday's installment opens with Meredith getting ready to head into work, where she's got two things to be nervous about: a joint press conference with Riggs about their recent heroics on the flight, and the conversation she has to have with Maggie (Kelly McCreary) to come clean about their relationship. Not helping matters is the fact that Maggie ambushes Meredith in the ladies room to give her a pep talk before her big presentation (and her favorite shirt, which Meredith forgot at home).

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But the true confessions part doesn't go according to plan. Maggie figures it out all on her own when Riggs affectionately - too affectionately - rubs Meredith's arm (for, like, a ridiculously long time) during their conference.

At first, Maggie tries to avoid Meredith entirely, vigorously scrubbing in on a surgery with Jackson (Jesse Williams). Then, she takes a more snarky approach, sitting down with Meredith at lunch and casually asking whether she and Riggs joined the mile-high club, and later stealing an OR out from Meredith's nose. But when Meredith finally insists that they talk like grownups, and accuses Maggie of being a "jerk," things take a turn.

Once Maggie discovers that Meredith and Riggs didn't hook up for the first time on the plane, and that their relationship goes back to before Maggie made her feelings about Riggs known, she's crushed. Remembering all the times she spent going on and on about Riggs to Meredith, Maggie says she was counting on being able to trust her half-sister after discovering that even her mother had lied to her (about her breast cancer). "You were all I had left," Maggie tearfully tells Meredith.

Elsewhere, Bailey (Chandra Wilson) takes it upon herself to repair the rift in Catherine (Debbie Allen) and Richard's (James Pickens Jr.) relationship, with mixed results. She accuses Catherine of not knowing how to be married to a man who's her equally and who loves and respects her. She encourages Catherine to set her ego aside and stop dismissing Richard. And Catherine surprisingly heeds her advice, going to the on-call room where Richard's been sleeping to smooth things over with him. Webber can't wait to show his wife pictures of the hundreds of roundworms he dug out of a patient earlier that day. (Yep, you read that right.)

And Richard and Catherine might not be the only couple that's reconciling. After Amelia (Caterina Scorsone) loses a cancer patient who dies immediately after giving birth to a premature baby, she has a breakdown in the elevator. When the doors open, Owen (Kevin McKidd) catches her crying and rushes in to comfort her. They don't exchange any words and he gets off at his intended floor, but... baby steps.

The ice even seems to be thinning between Maggie and Meredith by the end of the episode. As Meredith comes downstairs all set to go out for a sisters' night on the town that she had planned with Maggie and Amelia, it's clear that Maggie's intent on staying home with a magazine and some wine. But Meredith's not having it. "I'm sure as hell not losing you over a guy," Meredith tells her. Maggie reluctantly agrees to join them, but stresses that she's still mad at Meredith and might spend the whole night just talking to Amelia. Again, baby steps.

Grey's Anatomy airs Thursdays at 8/7c on ABC.