Science teacher Ms. Alamilla introduces the class to Blue 55, a whale who sings at a frequency no other whale can understand.

A classmate's botched sign language frustrates Iris, who pushes her and is sent to the principal's office.

Iris's mother confiscates all of Iris's beloved electronics as punishment for the school incident.

During her electronics ban, Iris researches Blue 55 online and posts a comment suggesting the lonely whale might be deaf.

Sanctuary scientist Andi Rivera replies to Iris, explaining that Blue 55 keeps singing despite no whale ever responding to him.

Iris enlists her school orchestra to record a song matching Blue 55's 55-Hz frequency.

Iris finishes composing the whale song and emails Andi, proposing they play it for Blue 55 from a boat.

Iris tries to convince her parents to let her attend the Alaska tagging expedition, but they insist she watch via webcast.

Iris sells her most precious Philco radio to Mr. Gunnar to fund a solo trip to Alaska.

A bank teller turns Iris away, saying she is too young to withdraw money without parental consent.

Iris confides her wish to Grandma, who offers to take her on the Alaska cruise she and Grandpa had planned.

Grandma books the Alaska cruise and she and Iris board a cruise ship together in San Francisco.

Blue 55 changes course toward Oregon, and the new sanctuary's staff refuse to play Iris's recording for the whale.

Iris uses her whale compass necklace to navigate on foot to the Lighthouse Bay sanctuary.

Mom agrees to let Iris transfer to Bridgewood school, where she can be with other Deaf students.

Iris first hears about Blue 55 in science class and is immediately moved by the whale's inability to communicate with others. After a school incident leads to punishment, she uses her forced break from electronics to research the whale and contact the sanctuary scientist tracking him. She composes a song at Blue 55's unique frequency with her school orchestra and urges the sanctuary to play it for him. When her parents refuse the Alaska trip, Iris sells her most treasured radio, is turned away by the bank, and enlists her grieving grandmother's help instead. Together they cruise toward Alaska, but Blue 55 changes course to Oregon, and Iris navigates alone on foot to find him. The journey ends with Iris diving into the water to meet the whale and, back home, finally winning her mother's permission to attend a school for Deaf students.

The core journey to reach a lonely whale.

Iris's grandparents find a beached sei whale on the day of her birth and name the newborn girl after the animal.

Ms. Conn dismisses Iris's handshape poem for not rhyming, ignoring its ASL rhyme structure; Iris throws it in the trash.

While hunting for junkyard parts, Iris instinctively tries to text her grandfather before remembering he has died.

After Iris's electronics are confiscated, brother Tristan helps her secretly bring a newly found Admiral record player into the garage.

Iris visits Grandma at Oak Manor and fails to start a handshape poem with the withdrawn, grieving woman.

Iris repairs a Zenith radio and places her hand on the speaker to feel the vibrations of Blue 55's recorded song.

Iris buys a compass engraved with a leaping whale from Mr. Gunnar's antique shop as a good-luck charm.

Iris visits friend Wendell and plays the 55-Hz piano key repeatedly to feel what Blue 55's frequency is like.

During a visit to Bridgewood school, Iris discovers for the first time that ASL has a history tracing back to France.

Iris checks Blue 55's tracking online and learns the whale has gone completely silent and stopped singing.

Iris and Grandma disembark at Juneau and touch the glaciers that Grandpa had always wanted to see.

Iris finds Grandma at a Skagway karaoke event, signing along to songs and drawing a large, delighted crowd.

Iris learns about a young blue whale named Mara at Lighthouse Bay who might one day communicate with Blue 55.

Using junkyard parts and waterproof caulk, Iris builds a submersible speaker and records her own voice saying she is there.

Sanctuary scientist Andi tours Iris through the facility after the whale encounter and says she could become an acoustic biologist.

The story begins on the day of Iris's birth, when her grandparents find a beached sei whale and name the newborn girl after it. At school, Iris's difficulties deepen when her teacher refuses to accept her handshape poem, and her grief over her late grandfather surfaces unexpectedly during a routine junkyard trip. While fixing radios and buying a whale compass, Iris slowly bonds with Blue 55 by feeling his song's vibrations through a speaker and playing his frequency on a piano. On the Alaska cruise, Iris watches her once-withdrawn grandmother come back to life at Juneau's glaciers and during a karaoke performance in Skagway. After the whale encounter, Iris receives a sanctuary tour and learns she has the makings of an acoustic biologist. She returns home knowing that both she and Grandma have finally found where they belong.

The people, objects, and quiet moments behind Iris's mission.

A whale pod abandons Blue 55 after his unusual sounds prove meaningless to them and they can no longer accommodate him.

Iris finds Blue 55's sheet music online and recognizes his repeated pattern as his own form of rhyme, like Grandpa's handshape poems.

Music teacher Mr. Russell agrees to help Iris record a whale song after she brings him Blue 55's sheet music.

Iris visits Bridgewood junior high with Wendell and discovers she cannot follow the other students' much faster, more advanced signing.

Wendell accidentally says he must sign like an old person for Iris, painfully highlighting how much Deaf community she has missed.

Andi's invitation to watch the whale tagging via webcast makes Iris more determined than ever to attend in person.

Iris's father plays humpback whale recordings through vibrating speakers and reveals he too once desperately wanted to find the whales.

Iris reads that people desperate to communicate always find a way, renewing her determination to reach Blue 55 in person.

Iris tells Wendell the full truth about her secret Alaska expedition while they look at Jupiter's moons together.

Bennie responds to Iris's note about her deafness with simple matter-of-fact directness, immediately and fully putting Iris at ease.

Iris and Grandma create a spontaneous handshape poem about a calving glacier, marking Grandma's joyful return to her old self.

Bennie urges Iris to be more understanding of Nina's imperfect sign language efforts, comparing them to Iris trying to speak whale.

When Iris risks missing the shuttle to the sanctuary, Grandma urges her to run ahead alone to arrive in time.

Iris's family arrives unexpectedly at the sanctuary for an emotional reunion after her encounter with Blue 55.

Grandma tells Mom she must allow Iris to attend Bridgewood, and Mom reveals her long-hidden fear of losing Iris to Deaf culture.

The story's turning points begin with the whale's own tragic perspective, as his pod abandons him after failing to understand his songs. Iris's discovery of Blue 55's sheet music leads to a recording session with the school orchestra, while a visit to Bridgewood school and Wendell's accidental jab make her feel cut off from even the Deaf community she longs to join. Her father's humpback whale memories and a passage about desperate communicators both push Iris toward her mission, and she secretly tells Wendell her plan while they stargaze together. On the cruise, Bennie's easy acceptance of Iris's deafness offers a model of genuine friendship, and a frank conversation about Nina forces Iris to reconsider her own empathy. The final turning points come when Grandma urges Iris to run alone to the sanctuary, the family arrives for a tearful reunion, and Grandma persuades Mom to finally let Iris attend Bridgewood.