In the timeline of the Marvel Cinematic Universe, ANT-MAN AND THE WASP takes place after the events of Captain America: Civil War and before Avengers: Infinity War. Scott Lang (Paul Rudd) is stuck counting the days until his house arrest -- the consequence of his decision to come to Cap's aid in Civil War -- is finally over. And his former associates Hope van Dyne (Evangeline Lilly) and her father, Hank Pym (Michael Douglas), are on the run from the authorities, using their advanced quantum technology techniques to run, staff, and hide an ant-maintained lab. When Hope and Hank discover that there's a possibility that Hank's long-missing wife, Janet van Dyne (Michelle Pfeiffer), is still alive somewhere in the Quantum Realm (which Scott visited briefly in Ant-Man), they strong-arm the reformed crook into helping them locate and rescue her. Complicating matters are two villains: smarmy black market broker Sonny Burch (Walton Goggins), whose rich clients want Pym's technology for themselves, and The Ghost, aka Ava (Hannah John-Kamen), who painfully phases in and out of the physical realm and blames Pym for her affliction.
