Relationships will be put to the test during Season 13 of “Grey’s Anatomy.”

During the premiere, Meredith (Ellen Pompeo) was forced to throw close friend Alex (Justin Chambers) under the bus. While he deals with the fallout from pummeling DeLuca (Giacomo Gianniotti), she is left questioning her loyalties in episode 2 of the ABC medical drama. This may also apply to her relationship with Maggie (Kelly McCreary), who feels betrayed after learning that Meredith and Riggs (Martin Henderson) have formed a budding romance.

While the two try to figure out where they stand in “Catastrophe And The Cure,” Owen (Kevin McKidd) and Amelia (Caterina Scorsone) are settling in to life as newlyweds. During the second episode they will host a dinner party, inviting unexpected guests to dine in their home. Meanwhile, Jackson (Jesse Williams) and April (Sarah Drew) are also dealing with new beginnings. Although they’re divorced, Jackson is prepared to make a deal with the new mother in the hopes of lightening her load as she recovers from a less-than-conventional birth.

When last we saw Alex he was behind bars following the revelation that it was him who assaulted DeLuca. He was arrested after Meredith confessed to Bailey (Chandra Wilson) that she knew what had happened. Meredith, who has been dealing with the chaos within Grey Sloan Memorial stemming from DeLuca’s hospitalization as well as a love-triangle between her, Maggie and Riggs, visits Alex in jail to apologize for turning him in. He appears sorry for what he’s done and aware that the worst has yet to come. Alex repeatedly tells Meredith he will likely be spending time in jail and lose his medical license, though she assures him he doesn’t know anything for certain. Her visit comes not long after a confrontation with Maggie over her secret relationship with Riggs.

Maggie is, as fans expected, hurt that her half sister has been hiding something from her and calls for an honesty pact. Meredith agrees to be honest with her sister, but immediately breaks that promise. Riggs visits her at home and the pair briefly discuss what’s going on. Meredith sends him away, telling Maggie it was just a stranger looking for directions.

The Meredith and Maggie drama should be expected from fans of the show. During an August interview with TV Guide, McCreary said that her character has had trust issues for some time and has made no secret of that. In Season 1, she struggled to overcome issues she had with Richard (James Pickens Jr.) — who is her biological father. With secrets lingering between her and Meredith, she and Maggie are sure to encounter some problems.

“One of the things that we know about Maggie, is that she is really a stickler for honesty and the truth,” McCreary said. “In her first season, she really holds it against Richard that he didn’t tell her [he was her father] right away, that he withheld the truth for any length of time. To me, that’s an indication of how we can expect Maggie to feel about any lack of honesty, any lack of full transparency and disclosure in a relationship — especially with somebody that she trusts and, more than trusts, really relies upon as much as Meredith.”

“Grey’s Anatomy” airs Thursdays at 8 p.m. EDT on ABC.

“Grey’s Anatomy” Fallout from Alex’s (Justin Chambers) brutal attack on DeLuca will leave Meredith (Ellen Pompeo) questioning her relationships. Photo: ABC