The Sky People are desperate to get revenge after what the Ice Nation did to the people at Mount Weather. It's going to be big in this week's episode of "The 100" season 3.

The trailer for episode 4, titled "Watch the Thrones" revealed the increasing tension between the Grounders and the Ice Nation. For tonight's episode, it's going to be filled with some action, considering there will be war between nations.

But the war between Sky People and the Ice Nation won't be the only story "The 100" fans will look forward to. Elsewhere in the episode, Lexa (Alycia Debnam-Carey) and Roan (Zach McGowan) will be fighting head-to-head gladiator-style. (Check out teaser photos below)

Based on the exclusive clip from the episode released by IGN, it's going to be an episode full of suspense as Lexa tries to defeat Roan. Both Lexa and Roan are fierce warriors but at some point, the former gets the upper hand when the latter loses his grip on his sword and for a moment became weaponless.

However, Roan is determined not to lose and he fights back even more, gaining control of the duel and kicking Lexa to the ground. Clarke (Eliza Taylor), who was there the whole time watching in suspense, was even more shocked to see Lexa go down. Will the commander get up on her feet?

The swordfight between the Prince of Ice Nation and the Grounder Commander is one of the highlights of season 3 McGowan had teased even before it premiered. Speaking to Collider last month, the actor described the duel with Debnam-Carey to be "really fun."

Meanwhile, speaking to IGN, Debnam-Carey also detailed her experience saying that they shot the scene in a day, and she felt sore in the following days. It was also the first time that the actress did a sword fight scene.

Catch the most anticipated battle between Roan and Lexa on "The 100," tonight at 9 p.m. EST on The CW. Check out more teaser photos here and watch IGN's exclusive clip of Roan and Lexa's fight below.