Hank eventually told his daughter what really happened to Janet. She went subatomic to deactivate a bomb, but was sent tumbling into the Quantum Realm. Scott's return trip from the very same place got Hank thinking about rescuing Janet and he began working with his daughter towards that goal.
However, Hope and Hank had to go underground after Ant-Man helped Captain America in Germany, breaking the Sokovia Accords. Because of their association with the hero, Hank and Janet had to go underground. They built a secret lab in a shrinkable office building and began working on a Quantum Tunnel. Upon trying the invention out for the first time, it failed, but Scott Lang had a dream about Janet and left a message with Hank.
Hope then went out, tranquilized Scott, set up a giant ant to maintain his house arrest for violating the Sokivia accord and brought him to the lab. They explained their theory that he had become entangled with Janet on a quantum level which would have allowed her to leave a message in his head. After hearing the full content of Scott's dream, they were convinced that Hope's mother was still alive and carried on with their plans.
A Ghost Of A Chance
Posing as Susan, Hope met with Sonny Burch to acquire a component that would stop the tunnel from overheating. When Burch tried to go back on their deal, Hope got in her Wasp suit, took out his goons and grabbed the device. However, Ghost appeared and gave her trouble. While Hope and Scott did get the component, the new player made off with the shrunk-down lab.
Without any of their equipment, Hope and the others sought out Hank's old partner Bill Foster. He gave them a way to track the lab while also secretly working with Ghost. After acquiring the old Ant-Man suit from Cassie's school, they used it to track the lab back to Foster's house where he was treating Ava Starr (a.k.a. Ghost). The young woman knocked out the two heroes and also grabbed Hank. When they all woke up, Ava recounted the story of how her father Elias Starr took several desperate risks after Hank Pym had him fired and discredited. The ensuing lab accident turned Ava into Ghost. Foster started helping her shortly after, though S.H.I.E.L.D. turned her into an assassin. Bill got her out after the organization fell apart.
Foster posited that they could extract the Quantum energy absorbed by Janet and use it to save Ava even if it threatened van Dyne's life. When Hank faked a heart attack, Hope tricked Foster into letting loose some shrunken ants and they escaped.
Hope and the others got the lab back, got it to a safe location and began updating the Quantum Tunnel. The process worked enough for Janet to take control of Scott's body and fix the algorithm to get the whole thing working properly. Hope watched as her "parents" altered the system to track Janet.
When Lang had to leave to not violate his house arrest, the FBI managed to nab Hope and Hank. Ghost took advantage of the situation and stole the lab, but Ant-Man helped Hope and Hank break out of custody. Meanwhile, Foster and Ava began the extraction process.
While Hank journeyed into the Quantum Realm to save Janet, Hope did her best to keep the shrunken lab safe. Along the way, she saved Scott's life after he grew too large and passed out in the water. The gamble worked and Hope was soon reunited with her mother. Hope did her part to escape the authorities after that.
With the heat off, Hope and Scott started seeing each other again. From there, Hope, Scott Hank and Janet attempted to gather elements from the Quantum Realm to save Ava. After Lang entered the Realm, though, Thanos snapped his Infinity Stone-adorned fingers and blipped out Hope, Janet and Hank while Ant-Man survived in the Quantum Realm.
The Wasp's Sting
Reconstituted along with both of her parents after the Avengers created a new Infinity Gauntlet and snapped everyone back five years later, Hope geared up and answered the call when Doctor Strange began opening portals to the location of a time-traveling Thanos' most recent attack on Earth.
The Wasp got in on the action right away and reunited with Scott, but they switched gears when the Avengers realized they needed to get the Infinity Stones back to their proper places in time so that Thanos couldn't get his hands on them. Van Dyne and Lang shrunk down and flew off to find Scott's van, which still had the Quantum Realm device in the back. The vehicle was dead, but Scott worked to hotwire it so they could get it started back up.
The effort ultimately proved fruitless as the van blew up during the attack. Hope didn't give up though, instead she focused on the invaders and keeping them from getting the Gauntlet. In fact, The Wasp joined up with Captain Marvel, Valkyrie, Pepper Potts and several other heroes to keep it out of Thanos' hand! Though they all fought hard, Iron Man managed to steal the Stones from Thanos and snap the intruders away. Tony perished wielding all that power. Hope attended his memorial alongside Scott, Hank and Janet.