Ant-Man and the WaspSave

1987 flashback. The Pentagon, deep underground. Hank Pym and his wife Janet van Dyne — both in original Ant-Man and Wasp suits — are intercepting a Soviet ICBM in mid-flight over the Pacific. The missile is carrying a 30-megaton nuclear warhead aimed at a US Navy carrier group. Standard sub-atomic shrinking won't disarm the warhead — the missile's plutonium core requires Janet to enter the molecular structure of the warhead itself and physically push the firing pin out of alignment. Janet does it. She crosses the subatomic threshold — disabling her own particles below the molecular scale. The missile fizzles out. Janet doesn't come back. Hank Pym, in the Pacific Ocean cockpit of the Quantum-shrinking ship he was piloting, screams her name. The shrinking gauge ticks past the safe limit. Janet's signal vanishes into the Quantum Realm. The opening prologue is the film's emotional setup. Hank has been mourning Janet for thirty-one years.

Present day, two years after Civil War (2016). Scott Lang (Paul Rudd) is under house arrest at his San Francisco apartment for violating the Sokovia Accords during the Civil War airport battle. He has ten more days on a two-year FBI surveillance bracelet. He's been forbidden from contacting Hank Pym or Hope van Dyne, who are also fugitives. He's been quarantined to his apartment with his daughter Cassie (Abby Ryder Fortson) and her stepdad Paxton's police monitors. He has been learning ukulele. He has been launching a small failing security-consulting firm with Luis (Michael Peña), Kurt, and Dave. He has been bored.

Hank Pym and Hope van Dyne (Evangeline Lilly), meanwhile, have been on the run as federal fugitives for two years. They've been hiding their lab inside a mobile-bunker truck — a shrinkable laboratory disguised as an ordinary cargo van that Hank can collapse to keychain size when needed. They've spent the last two years using all the data Hank had from the original 1987 Pym Particle program to design and build a working Quantum Realm tunnel. The tunnel can establish a stable wormhole to the subatomic dimension Janet disappeared into thirty-one years ago. Hank now believes Janet is still alive down there — time may run differently at the subatomic scale, and her cellular structure may have been preserved by the realm's quantum-physics anomalies.

Scott's vision. The morning before the planned Quantum Realm activation, Scott — in his San Francisco apartment — has a sudden hallucinatory experience while playing with Cassie. He sees Janet van Dyne in his mind for several seconds, walking toward him through fog, smiling. The vision passes. Scott has no idea why he just saw a woman he never met. He calls Hope on a smuggled cell phone. Hank and Hope immediately suspect this is what they've been hoping for: when Scott was in the Quantum Realm in Ant-Man (2015)'s final battle, his cellular structure briefly synchronized with Janet's at the subatomic level. Scott has been holding a quantum-entanglement-receiver signal in his brain for two years. Janet has been using him as a postal address. They've found her. They need Scott back at the lab immediately. They send Luis to break Scott out of house arrest.

Scott escapes house arrest by sending a giant-ant doppelganger of himself into his apartment to fool the FBI surveillance system — the ant in Scott's slippers is now sleeping in Scott's bed, with motion-triggered FBI ankle bracelet alerts. Luis drives him to the Pym mobile lab. The reunion is awkward — Hope and Hank are still pissed at Scott for getting them implicated in the Civil War events two years ago. They put him on the Quantum Tunnel rig. Scott connects with Janet's mental projection for thirty seconds — long enough to receive a precise location coordinate in the Quantum Realm. Hank now has a homing signal for his wife.

Sonny Burch and Ghost. Hank's plan requires a specific quantum-coil component that he sources from a black-market dealer in San Francisco's tech-trafficking underground. The seller is Sonny Burch (Walton Goggins), a Texas-accented small-time tech fence who has been quietly tracking Pym for years hoping to obtain the Quantum Tunnel technology to sell to government and military buyers. Burch double-crosses Pym during the exchange and attempts to seize the entire mobile lab. Then a third party arrives — Ghost, a masked, phasing female mercenary in tactical exo-armor who can pass through walls, floors, and human bodies. Ghost steals the Quantum Tunnel coil from Burch's warehouse and disappears through a wall.

Ghost is Ava Starr (Hannah John-Kamen). She has been molecularly unstable since she was a child — her father Elihas Starr, a former research partner of Hank Pym in the 1980s, was killed in a Quantum-Realm experiment that exposed five-year-old Ava to a quantum-scale energy burst. Her body has been phasing in and out of normal-matter alignment for thirty years. She has been in constant physical pain. She has been hidden inside an experimental SHIELD black-site since age six, then escaped years ago. Her body has been deteriorating for the past two years — her molecules are losing cohesion. She has months to live unless she absorbs sustained Quantum Realm energy directly from Janet. She has been working with Dr. Bill Foster (Laurence Fishburne), Hank's old SHIELD research partner who was the original Goliath super-sized version of Ant-Man and who has been a longtime rival of Hank. Bill has been training Ava and helping her survive.

Mobile-lab chase. The Quantum Tunnel coil that Ghost steals is the only one available. Hank, Hope, and Scott chase Ghost and Bill Foster through downtown San Francisco. The chase is one of the most-inventive set pieces in Phase 3 — Hank's lab is on wheels, the Pym Particle keychain can shrink it to thumbsize at command, but it can also be enlarged unexpectedly mid-chase. At one point a Hot Wheels Matchbox car the size of a thimble grows into a full-sized Cadillac that flips an SUV across a downtown street. At another point an entire pursuit truck shrinks to the size of a coffee cup and is picked up by Scott in his Ant-Man suit. The chase ends with Ghost capturing Hank and Hope and bringing them to her hideout. Bill Foster explains his vendetta to Scott — Foster blames Hank for Elihas's death and the destruction of Ava's life. He's willing to use the Quantum Tunnel to extract Janet's quantum energy to save Ava, even if it means killing Janet in the process.

Janet returns. Hope and Scott break free of Ghost's containment with Scott's giant-mode (Scott can now grow to fifty feet tall for short bursts thanks to a new Pym Particle enhancement). They wreck Ghost's lab. They steal back the Quantum Tunnel coil and reassemble the mobile lab. They activate the Quantum Tunnel for the first time over the San Francisco Bay. The lab descends into the Quantum Realm. Hank, in the descent vehicle, navigates through the subatomic dimensional layers using Scott's mental coordinates. He locates a colony of Tardigrades, then a luminescent-green field, then a small humanoid figure standing on a quantum-dust island. Janet van Dyne (Michelle Pfeiffer) — alive after thirty-one years, her hair partly turned gray, her Wasp suit faded — walks toward the descent vehicle. Hank hugs her. They kiss. Janet has been an honorary Quantum Realm citizen for three decades.

Janet's stabilization gift. Janet, who has spent thirty-one years learning the quantum realm's metaphysical properties, recognizes Ava's predicament. She uses her Quantum Realm energy reserves to stabilize Ava's molecular structure temporarily — through a controlled touch, not extraction. Ava is stable for the first time in thirty years. She's healed but not cured — she'll need ongoing maintenance. Bill Foster and Ava agree to disappear quietly with Janet's blessing. Sonny Burch is arrested. The Quantum Tunnel is hidden again.

Coda. Scott returns to his apartment in time for the FBI's surveillance bracelet to register him as compliant. Two minutes later FBI agents arrive for an unannounced inspection. Scott is in his bedroom in his pajamas eating breakfast cereal. The doppelganger ant is now under his bed. His house-arrest term ends successfully. He walks out of his apartment for the first time in two years. He stares at the San Francisco sunset. He's free. He hugs Cassie. The film's main story closes with the Pym family — Hank, Hope, Janet — reunited and Scott officially free.

Mid-credits. Days later, Scott, Hank, Hope, and Janet have built a small portable Quantum Tunnel inside Scott's van. Scott is going to use it briefly — a five-hour Quantum Realm trip to gather quantum-energy samples to study Ava's stabilization further. Hank, Hope, and Janet are at the controls outside the van. Scott climbs into the tunnel. He shrinks. He enters the Quantum Realm. He starts gathering samples. He says into his comm: "Test 21A — Quantum Healing Samples, in. Pulling Quantum Energy from samples. Aaaaand, that's a wrap." He laughs to himself. He's having a good day. "All right, you ready to pull me out? Hank? Hope? You there? Quantum Healing Samples in five seconds. Janet? Hank?" The comm goes silent. Up on the surface, Hope, Janet, and Hank are crumbling into dust. The Snap from Infinity War (2018) has just happened in mid-frame — they're three of the half-of-the-universe Thanos has just disintegrated. The Quantum Tunnel they had been operating ceases to function. Scott is now trapped in the Quantum Realm. He has no way out. He doesn't yet know what just happened. The film's most-debated cliffhanger ending plays out in real time.

Post-credits. The same scene as the mid-credits but from Scott's perspective in the Quantum Realm. Scott, in the subatomic field, has been waiting for the Quantum Tunnel's recall signal for forty minutes. The dimensional aperture has not opened. He stands in the Quantum Realm dust. He calls out for help. He doesn't yet know that he's the only Avenger-adjacent hero who survived the Snap. Cut to black. The audience knows. Scott does not. The film ends with a single-line title card: "AND ANT-MAN AND THE WASP WILL RETURN" — except they won't, until five years pass in-universe for Scott in the Quantum Realm. The Endgame setup is officially live.