Callie (Sara Ramirez) and Arizona (Jessica Capshaw) will face a big conflict in the next episode of Grey's Anatomy season 12.

In the previous episode, Callie chose to move to New York City with her new lover Penny (Samantha Sloyan). But her decision will affect her former wife Arizona, since she wants to bring their daughter Sophia with her when she moves to the Big Apple. This made Arizona upset, which is why she decided to file for full custody so Callie can no longer bring Sophia with her to New York.

However, Callie has no idea about what Arizona did. They will face the repercussions of their decisions in the upcoming episode titled "Trigger Happy." Will Callie contest Arizona's custody claim and fight for her rights for their daughter?

Meanwhile, the doctors from Grey Sloan Memorial Hospital will work together to save the life of a young boy who was shot accidentally by his playmate.

Based on the trailer for the upcoming episode, the young boy is fighting for his life after his playmate accidentally pulled the trigger of the gun owned by his mother. This tackles the highly controversial gun ownership issue that has been dividing the nation at the moment. Even the doctors will have a debate about it while treating the patient on the operating table.

The official synopsis for 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."

Fans are also expecting to see how April (Sarah Drew) and Jackson (Jesse Williams) deal with their own custody issue regarding their still unborn child. In the previous episode, the ex-couple managed to set their angers aside and had a ceasefire when they talked about their child. But will this last?

"Grey's Anatomy" season 12 episode 20 airs Thursday, April 21, on ABC.