Callie and Arizona's custody battle comes to a heartbreaking close in "Grey's Anatomy" season 12, episode 22. The episode is titled "Mama Tried" and shows the ex-lovers making their case on why each of them deserves to have custody of their daughter Sofia.

The promo for the episode shows Callie making clear that Sofia is more than just her daughter but her lifeline while Arizona states that she wants Sofia with her and her only.

By the end of the "Grey's Anatomy" season 12 episode, only one of them will win the custody over the child. The clip does a good job at showing the tension inside the courtroom. The anxiety in Callie and Arizona's eyes as they await the decision of the judge says it all.

What's more interesting about this episode is that their friends will also be taking sides. Owen and Meredith are joining Callie in her fight while Webber will be making statements in support of Arizona. Because of this, fans can also expect tension to rise and follow the doctors all the way to Grey Sloan Memorial Hospital.

In the previous episode, Callie decided to bring Sofia to New York, where her girlfriend Penny will work as part of the privileges of winning the Preminger Grant. Arizona is understandably furious about it and insisted that Sofia is not coming with her.

As fans may have already heard, Sara Ramirez, who plays Callie, will be leaving "Grey's Anatomy" after season 12. Whether or not this will influence how things turn out for her character's legal battle remains unclear.

Elsewhere in "Grey's Anatomy" season 12, episode 22, Alex and April will team up to save the life of a pregnant teen with a medical condition.

"Grey' Anatomy" season 12, episode 22 ,"Mama Tried" will air May 5 at 8 p.m. ET on ABC.