However, when his daughter Cassie (Kathryn Newton) shows him, Hank Pym (Michael Douglas), Hope Van Dyne (Evangeline Lilly) and Janet Van Dyne (Michelle Pfeiffer) an invention that sends a signal down to the Quantum Realm, Janet tells her to turn it off immediately, but it's too late.
Find out what happens (and who turns up!) by watching the action-packed trailer above. ~Alexandra Heilbron