In the next episode of "Supergirl" season 3, Kara Danvers aka Supergirl (Melissa Benoist) will struggle to wake up from her coma after being placed in that condition by the villainous Reign aka Samantha Arias (Odette Annable).

The trailer for the upcoming installment titled "Legion of Superheroes" was recently released and it shows Kara's sister Alex (Chyler Leigh) trying to save her from her injuries. The superhero apparently is in critical condition but the medical staff is able to stabilize her for the meantime.

Unfortunately, she is now trapped in a coma where she cannot get out very easily. Kara recalls how she fought with the seemingly powerful Reign, who held her by the neck and dropped her from a very tall building.

"Reign is still out there. People are dying," Kara thinks to herself. She has to find a way out of her deep sleep.

Meanwhile, Alex is doing whatever she can to snap Kara out of her coma. "Stay with me, Kara, stay with me," she says to her sister.

Apparently, Kara has to remain in a water chamber in order to help her regain consciousness. However, the readings from the electrical pads attached to her head still do not show any progress.

In the meantime, it seems like Mon-El (Chris Wood) and his companions are going to step up and fight against the nefarious Reign and her mysterious agenda.

In the last episode, Supergirl came face-to-face with Reign, who wasted no time in pounding her to the ground. This latest villain threw the bloodied superhero off a building without much effort. Supergirl crashed onto the cement and was knocked out cold. Alex and her team quickly retrieved her and brought her to safety.

"Supergirl" season 3 episode 10 will air on Monday, Jan. 15, 2018 at 8 p.m. EST on The CW.