The fourth season starts with Harry and his baby Bridget stuck in prison on the Grey Moonbase, while a shape-shifting Alien called a Mantid has taken over his body on Earth passing himself off as the real Harry Vanderspeigle. Harry manages to escape the Greys and arrives back on Earth for a showdown with the Mantid Alien, but soon finds he may not have what he needs to finish the job. Asta and D'arcy struggle to keep a secret from Ben and Kate, who are both desperate to find answers to what has been happening to them. Sheriff Mike and Deputy Liv attempt to solve some mysterious deaths in Patience that Sheriff Mike is beginning to think aren't caused by anything human.

Extraterrestrial interloper Harry Vanderspeigle and General McCallister put aside their differences and work together in the face of a much greater existential threat - the impending invasion of the Greys.

In season two, Harry is once again stranded on Earth where he must confront the consequences of having failed his people's mission to destroy the human race. On his new quest to protect the people of Earth, Harry struggles to hold on to his alien identity as his human emotions grow stronger by the day. In an adventure that takes Harry and Asta all the way to New York City, Asta brings Harry into the arms of someone he can call family. While back in Patience, Sheriff Mike and Deputy Liv find themselves closer to unraveling the mystery of Sam Hodges's murder.