'Grey's Anatomy' season 13 episode 4 spoilers: Meredith and Nathan gets more serious? What happens to Maggie?

The fourth episode of "Grey's Anatomy" season 13 will be exploring the romantic relationships of some the show's couples and will see them defining what their relationships truly mean.

Episode 3, which aired last Oct. 6, somehow set the stage for what's to happen in the upcoming episode. Titled "I Ain't No Miracle Worker," the episode saw Arizona (Jessica Capshaw) and Alex (Justin Chambers) arguing because of DeLuca (Giacomo Gianniotti).

It will be recalled that during the season 12 finale, Alex beat DeLuca to a pulp after finding him inside his apartment. He thought DeLuca was having an affair with his girlfriend Jo (Camilla Luddington). Because of his jealous rage, DeLuca ended up in the hospital, and Alex is now awaiting trial to see if he will be charged with felony in the second degree.

In the last episode, Alex felt he had it up to here with all the lectures he's been getting about what he did, so he snapped when Arizona confronted him in the hospital. In the same episode, Meredith (Ellen Pompeo) found herself in a quandary concerning her love life.

According to TV Line, Meredith's half-sister, Maggie (Kelly McCreary) asked her for advice as to whether she should ask Nathan Riggs (Martin Henderson) out. The thing is, Meredith and Nathan have a thing going between them, and instead of coming out clean to Maggie about it, Meredith chose to urge Nathan to go out on a date with her half-sister and act like a "jerk" so Maggie will beg off from crushing on Nathan.

On Thursday's episode titled "Falling Slowly," Alex will try to do what he thinks is right. However, it looks like ladyluck is staying elusive. It also looks like Maggie will find out the truth about Meredith and Nathan and will get upset over it.

"Alex tries to do the right thing but still can't catch a break. Jackson and April adjust to their 'new normal' with the baby. While Meredith and Nathan establish what's going on between them, Amelia questions the state of her relationship with Owen," reads the synopsis for the upcoming episode.

Maggie and Meredith's relationship is already rocky, and the former learning about the real deal between Nathan and her half-sister might only make things worse for them. Amelia (Caterina Scorsone) will also question the status of her marriage with Owen (Kevin McKidd), which is barely starting. It remains to be seen what made her question her marriage.

"Grey's Anatomy" season 13 episode 4, "Falling Slowly," airs Thursday, Oct. 13, at 8 p.m. ET on ABC.