It may have started out with hookups, but it looks like Riggs (Martin Henderson) wants to make things between him and Meredith (Ellen Pompeo) a little more serious when "Grey's Anatomy" season 13 returns.

Episode 4, which is titled "Falling Slowly," promises a development on the budding (and what fans hope believe is promising) relationship of Meredith and Riggs.

Whatever the two have just got more complicated after Maggie (Kelly McCreary) decided to make the first move on her sister's hookup buddy, which is still unbeknownst to her.

In "Grey's Anatomy" season 13 episode 4, it will be made clear that Riggs might be much more into Meredith, who he tries to convince to "hang out" in the promo.

"I don't hang out," Mer said mockingly in reply. "You could," Riggs responded. However, the clip warned that "mixing business with pleasure could have deadly consequences."

In this case, it looks like it involves the life of a patient. Owen (Kevin McKidd) believes that she should be in surgery while Meredith counters that there is no reason for that with Riggs seconding her.

However, it looks like the support of Riggs on Mer about this does not have anything to do with what the relationship they have, and the latter will realize that in "Grey's Anatomy" season 13 episode 4.

"You did not side with me because of you and I," Meredith told Riggs in the "Grey's Anatomy" promo. Riggs looked like he had no reason to hide that yet.

Whatever it is, it might have something to do with Riggs and Owen's beef with each other, which is yet to end. It appears that it will not die down anytime soon either.

"Grey's Anatomy" season 13 episode 4 will also offer major developments for other characters. The synopsis reads: "Alex tries to do the right thing but still cant 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."

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