第四季中，假Harry（偽裝的螳螂）可能會大肆破壞，而真Harry 的盟友們則試圖想辦法把他從邪惡的灰人的魔掌中解救出來。 此外，Mike發現外星人是真實存在的，這無疑會在他多年的猜疑之后改變他的性格，他可能會轉而幫助Harry。不管怎樣，《外星居民》第四季將以Harry 處于危險境地開場，地球的毀滅似乎比以往任何時候都迫在眉睫。 （據說，所有演員繼續，只有老女將軍可能沒確定，希望她也繼續）

season 4 could see the fake Harry (Mantid in disguise) wreaking havoc as the real Harry's allies try to find a way to rescue him from the clutches of the evil Greys. Furthermore, Mike's discovery that aliens are real will undoubtedly transform his character after years of suspicion, and he might come around to helping Harry's cause. Either way, Resident Alien season 4 will start with Harry in a precarious position, and the destruction of Earth seems more imminent than ever before.