The Night Master's Lair is where the Night Master lives. When he was defeated, Grizzleflavin was guarding it. Many villains tried to get in but they failed. G.P, Flaviour, and Charles tried break in to the lair, but for that they needed a flaming soul, an evil heart, and a pair of groovy pants, or at least a spare key. Coop had the spare key so G.P, Flaviour, and Charles go to Coop's party. Yin and Yang stop them in a fight but when the key to the Night Master's Lair broke up, the power of the key got inside G.P and he got a new suit, new powers and evil magic. G.P also gave himself a new name: Fr-ped. Fr-ped dumps Flaviour and Charles by saying: "shut up flunkeys!" and then goes back to Night Master's Lair, but couldn't go inside because: power didn't make him Evil enough. Fr-ped was angry and goes away. Next, Kraggler tried to go inside but he had to do some evil stuff so he goes to town goes to town and does all kinds of it including overturning a car, turning F. Elf Schelfmann into an old guy and kicked him aside, throwning a mailbox in a tree, splashing water at a puppy from a fire hydrant, ripping a tag off a mattress so two guys carrying it wouldn't sell it, chopping Dave in half, breaking up a couple, giving Coop a wedgie, and then turning him old. When Kraggler goes back to the Night Master's Lair, Grizzleflavin says that he hasn't done enough evil; to add result to injury, he's defeated by the combined efforts of Yin, Yang, and baby Yo. In Deja Foo, Ultimoose goes in to the Night Master's Lair, by getting Grizzleflavin to forget who is the Night Master, but Yang spoiled his plan. Coop is the only one who can go inside the lair, because he had the Night Master's energy. In Welcome to the Dark Tomorrow, Yin and Yang got inside the Lair and had a party. The League of Evil was broke in and tried to spot the Lair, but Yin kick them all out. When Yang brings Eradicus back to life he starts the Dark Tomorrow; but, Yin, Yang, and Master Yo saved the day. In Gone a Fowl, Coop turned Yin evil to be her girlfriend Yin she almost entered the Night Master's Lair with Coop her evil temporarily boyfriend she almost killed her brother Yang when Yo got the bow tie and suspenders and made Yin back to normal but she mysteriously find out that Lina likes Yang when she saw them holding hands When Eradicus was defeated, the world was saved again, everything went back to normal, and the Night Master's Lair was destroyed.