Fiery scenes are expected in the first part of the finale of "The 100" season 3.

The episode, titled "Perverse Instantiation – Part One" centers on the all-out war that Clarke (Eliza Taylor) and the gang will stage against Jaha (Isaiah Washington) and the evil AI ALIE (Erica Cerra).

In the previous episode, Raven Reyes's (Lindsey Morgan) attempt to destroy ALIE by pulling her plug did not go according to plan. This means that the rebels have to think of another plan to ultimately end ALIE's attempt to control everyone's mind.

At the moment, Clarke and Raven are joined by Harper McIntyre (Chelsey Reist), Jasper Jordan (Devon Bostick), Monty Green (Christopher Larkin), Bellamy Blake (Bob Morley) and his sister Octavia (Marie Avgeropoulos), Miller (Jared Joseph) and Bryan (Jonathan Whitesell) in their quest to eliminate ALIE. But it seems that the group needs more in order to succeed.

Meanwhile, an unlikely alliance between the Grounder Indra (Adina Porter), the former Anti-Grounder chancellor Charles Pike (Michael Beach), and the rebellious John Murphy (Richard Harmon) are also working together to get rid of ALIE. Will they choose to work with Clarke and the gang for a common purpose?

Also, the previous episode showed that Clarke's attempt to encourage Luna (Nadia Hilker) to become the next Grounder Commander failed. ALIE's plans to put Ontari (Rhiannon Fish) in the position could become successful. So Clarke decided to seek the help of Ice Nation's King Roan to help them stop Ontari's takeover in the position. But Bellamy is still unconvinced if Roan should be trusted.

The official synopsis for the episode reads:

"Clarke is going to find hope in the most unlikely place. In the meantime, Alie's master plan will end up coming together."

"The 100" season 3 episode 15 is slated to air on Thursday, May 12, on The CW.