The Corridor of Elders Ninjago: Masters of Spinjitzu : Season 4 Episode 10

The ninja and fighters discover there's a strategic location called the Corridor of Elders where they can make their last stand against Chen's Anacondrai army... but even with new Destiny Bounty, their forces still aren't strong enough. Fortunately, Pythor escapes Chen's clutches and discovers there is one spell in the Book of Magic that could stop the war, but at a a serious cost.