After witnessing a lot of emotional ups and downs, Grey's Anatomy season 12 returns with episode 20 titled Trigger Happy. The episode will deal with the social issue of the Arms Rights Act as the doctors at Seattle's Grey Sloan Memorial Hospital struggle to save the life of a young boy who was shot accidentally.

Click here to watch the episode via live stream on ABC Go, or click here to watch it online on the ABC website (only in the US).

A sneak peek of the upcoming episode of the medical drama released by ABC reveals Amelia Shepherd, Owen Hunt and their team trying to save the life of eight-year-old Brandon, who was accidentally shot by his friend while playing with his mother's gun.

Apart from the social cause, the show will also focus on Callie Torres and Arizona Robbins as they argue over their daughter Sophia's custody.

The synopsis of the episode reads: The doctors work frantically to save a young boy who was accidentally shot. Meanwhile, Arizona is upset when Callie tries to make an important decision about Sophia's future without consulting her.

ABC has released a sneak peek where Callie appears overly excited while informing Arizona about her new rented apartment in New York and how it is close to some of the best schools. However, the chief paediatrician has already sensed her former partner's plans and has sought legal options in order to keep her daughter in Seattle.

"Somewhere, sometimes, you heard me say yes to this. You heard me say, 'Yes, please, Callie, take my daughter across the country' but I never said that. Go. Be happy. Have your Penny. You're just not taking my daughter with you," she snaps back at Callie who has plans ready to make a new beginning with Sophia and Penny.

Grey's Anatomy season 12 episode 20 will air on 21 April at 8/7pm CT on ABC.