Jack is a young elementary school student studying poetry in Miss Stretchberry's class for a second year. He carries a heavy burden of grief over the death of his yellow dog, Sky, which makes him resistant to forming new emotional attachments. He prefers writing short lines of free verse that allow him to express complex feelings without worrying about grammar or punctuation.

Miss Stretchberry is an empathetic, encouraging educator who tailors her teaching methods to foster creativity rather than strict compliance. She introduces her class to famous poets and various literary devices, always emphasizing that personal expression matters more than technical rules. Her classroom serves as a safe haven for her students to explore their voices.

Jack's mother is a warm, hardworking woman who happens to be deaf. She communicates using sign language and connects with the world through movement and rhythm. She fully supports her son's creative endeavors and actively participates in his learning by feeling the physical beat of his poems.

Uncle Bill is a college professor with strictly traditional views on what qualifies as literature. He insists that real poetry requires rhyme, regular meter, and grand subjects like war or death. His pedantic attitude actively discourages young writers and makes him a difficult guest at family gatherings.

A neighborhood stray that serves as the immediate focus of Jack's ire. Following an incident where Jack attempted a rescue and received scratches instead, the feline becomes the primary subject of his negative poems. It aggressively defends itself and remains aloof from human affection.

Skitter McKitter is an energetic, bouncing black kitten with white dots. The small animal quickly integrates into the household, leaping across furniture with an acrobatic grace that inspires new poetry. Her arrival tests her new owner's resolve to never care for another pet.

Sky is a deceased yellow dog whose memory heavily influences the present events. He was a joyful companion whose sudden death in a traffic accident left a lasting trauma on his young owner. The lingering grief prevents his family from easily moving on or adopting new animals.

Jack's dad is a caring presence in the household who gently tries to help his son move past a period of intense grief. He attends school conferences to stay involved in his child's education. He supports the idea of bringing a new pet into the home.

A famous living poet and author whose work serves as a major inspiration in the classroom. He generously corresponds with younger readers and shares small details about his own life. His personal fondness for felines causes some confusion for his biggest fans.