'Marvel's Agents of S.H.I.E.L.D.' season 3 episode 14 spoilers: Mack's relationship with brother compromised because of threats to Inhumans

Mack (Henry Simmons) and his brother Ruben (guest star Gaius Charles) reconnect in the next episode of 'Marvel's Agents of S.H.I.E.L.D.' season 3.facebook.com/AgentsofShield

The Inhumans are in danger in the next episode of "Marvel's Agents of S.H.I.E.L.D." season 3.

In the episode, titled "Watchdogs," a terrorist group is aiming to obliterate all the living Inhumans. The official synopsis reads:

"When a radical group called The Watchdogs emerges with plans to eliminate the Inhumans, Agent Mack and his brother become caught in the crossfire. Meanwhile, Simmons discovers a powerful chemical compound that could alter the future for Inhumans."

The synopsis mentions that Agent Mack (Henry Simmons) and his brother Ruben (guest star Gaius Charles) will reconnect since the S.H.I.E.L.D. agent will try to have some down time after hitting a rough patch when he lost his fellow agents Bobbi (Adrianne Palicki) and Hunter (Nick Blood).

Mack will find it hard to deal with the loss of two of his closest friends in S.H.I.E.L.D. But according to Simmons, this will be an interesting time for the viewers to get to know more personal details about his character.

"They're exploring a little bit of his life outside of S.H.I.E.L.D.," Simmons said during Saturday's WonderCon panel for the show, as reported by Entertainment Weekly. "The opportunity where they explore how lives are affected, families are affected, by if someone is S.H.I.E.L.D. and they aren't allowed to tell, 'Hey, I'm in S.H.I.E.L.D.' They're not allowed to talk about that, and just how relationships are delicate and strained when you're in S.H.I.E.L.D. and you can't really tell anyone what you're doing. It's difficult."

Meanwhile, IGN revealed that the episode will also feature the return of a familiar face which was not seen since "Marvel's Agents of S.H.I.E.L.D." season 1. However, there are no details yet pertaining to the identity of the character who will re-enter the series this season.

Also, fans will find out that Daisy (Chloe Bennet) will have a great rapport with Fitz (Iain De Caestecker) when they begin working with each other on a very important mission.

"Marvel's Agents of S.H.I.E.L.D." season 3 episode 14 airs on Tuesday, March 29, on ABC.