"Supergirl" season 2 ended with Kara Danvers' (Melissa Benoist) heroic act of letting Mon-El (Chris Wood) go. Before Supergirl's success in saving National City, Daxamites almost conquered Kara's home. They aimed to build a new Kingdom led by Queen Rhea, Mon-El's mother. However, to stop Rhea (Teri Hatcher) from destroying the city, Kara decided to challenge her through Dakkam Ur. It is an ancient trial by combat, which is commonly known in the planet of Daxam.

Supergirl bids goodbye to Mon-El

Kara Danvers thought that she could have it all: the love of her life, family, friends and being the National City's superhero.

Unfortunately, "Supergirl's" season 2 finale made her choose between the safety of many and keeping the man she loves the most. While Kara manages to win the combat, Rhea did not abide by the rules. She ordered the Daxamite soldiers to destroy the city, even after her defeat continually.

It is what she called "Plan B," just in case something goes wrong with the battle. On the other hand, this led Kara to execute her backup plan as well. The DEO, with the help of Lena Luthor and her mother, designed a tech that will release lead to the atmosphere. Sadly, this move is toxic to all Daxamites, including Mon-El. The enemies have no choice but to fall back, leaving Kara Danvers in pain after the departure of her Daxamite boyfriend.

Despite what happened, Kara wanted everyone to remain happy. Her cousin Superman (Tyler Hoechlin) was overwhelmed by how she handled the situation. Clark Kent shared that he could not have done it, choosing between her love Louise Lane or the world. Our girl of steel is indeed the champion of the earth! Meanwhile, Mon-El left the planet earth through a pod he used when he first arrived.

Will Chris Wood ever return?

According to Entertainment Weekly, Chris Wood's return remains a mystery though the second season cast him as a series regular. While viewers do not know until when this serves as a chance for his possible return. Additional newcomers who entered season 2 along with "The Vampire Diaries" alum are Floriana Lima as National City Police Department Detective Maggie Sawyer (Alex Danvers' girlfriend), Ian Gomez as journalist Snapper Carr, former Wonder Woman Lynda Carter as the President of the United States and Hoechlin as Superman.

Furthermore, CBR.com revealed that the main villain of season 3 is Reign, which will be played by Odette Annable. The said character was first introduced in 2012's Supergirl #5 comic book.