William is a fifth-grade boy who acts as the narrator of the story. Following his father's sudden departure, he takes on a protective role toward his mother and younger sister. He hides his own hurt behind a quiet exterior and approaches the sudden adoption of five pets with heavy skepticism.

Joe is a literature teacher who abruptly leaves his family to seek creative inspiration for his writing. He communicates his exit through written notes rather than speaking directly to his children. His absence creates an immediate void in the household.

Janey is a mother who impulsively adopts four dogs and a cat immediately after her husband leaves. She struggles to explain the situation to her children, relying on formal breakfast table settings to manage the household's distress. She fills the quiet house with life to mask her uncertainty.

Elinor is William's four-year-old sister who views the world with unquestioning belief. She carries a toy wand and insists the newly adopted pets possess magic. She asks direct questions about her father's absence and maintains a list of forbidden words her parents use in anger.

Bryn is a sturdy brown dog who assumes a leadership role among the newly adopted pets. She immediately claims the empty space in Janey's bed, acting as a constant companion for the household.

Bitty is a small, high-energy terrier adopted from the local shelter. She adopts a vigilant role in the house, perching at the window to keep watch over the neighborhood.

Grace is a gentle, retired racing greyhound. She naturally gravitates toward Elinor and acts as a silent guardian for the young girl. She prefers tepid water and exhibits a calm presence.

Neo is a massive white and gray Great Pyrenees mix puppy. Despite his large size, he possesses a soft nature and forms a quiet bond with William.

Lula is a cat adopted from the shelter at Elinor's specific request. She displays remarkable patience and tolerates Elinor's attempts to dress her in baby clothes.

Gran is William and Elinor's grandmother who brings comfort to the family through her constant knitting projects. She understands the nature of childhood belief and suggests to William that magic requires emotional bravery.

Grandfather Will provides quiet solidarity to his grandson William during the family crisis. He offers practical support and recognizes the emotional strain caused by his son-in-law's sudden departure.

Marvelous Murphy is Janey's eccentric friend and an aspiring writer. She brings dress-up necklaces for Elinor and views the world with a whimsical enthusiasm.

Max is William's fifth-grade classmate. He visits the house and provides a sense of normalcy for William away from the tense household environment.

Julia is an employee at the local animal shelter. She assists the family with their impulsive decision to adopt multiple pets on the same day.