The 100 season 3
Roan with a captured Clarke in The 100 season 3 episode 15 pictures The CW

Part 1 of The 100 season 3 finale airs on 12 May at 9pm EST on The CW . Episode 15 is titled, Perverse Instantiation, where Clarke, Bellamy, Octavia, Raven and the rest of the group will enlist the help of Roan, the king of the Ice Nation.

The official synopsis reads as follows:

Click here to watch the episode online on The CW website (only in the US).

The promo of the episode opens with Clarke, and Bellamy trying to convince Roan to be on their side and help them defeat Alie. Clarke tells Roan, "The enemy we are up against is after everyone. Like it or not we need each other." To which, Roan simply replies, "So when do we leave?"

Clarke tells Roan about Alie's network and explains, "Whatever one sees they all see, whatever one hears, they all hear." Then we see Alie telling Luna, "We can't let them have you," as Luna is the only night blood who can take the Commander chip and end Alie for good.

The 100 group comes up with a plan to attack Alie, but Bellamy does not trust Roan. Bellamy asks Clarke, "You are really willing to trust that guy with your life?" Meanwhile, we see Monty and Indira are continuing with their mutiny to defect Alie.

The promo then shows Monty saying, "They are walking into a trap..." as wee see Roan taking a captured Clarke to Polis, and Bellamy, who is on the watch with Octavia says, "Something is not right!"

Is Clarke's plan to trust Roan a trap set up by Alie? Fans will have to wait and watch The 100 season 3 on 12 May to find out.