Poppy is a cheerful, optimistic teenager living in Blossom Grove, Georgia. Known for playing the cello and wearing unique bows in her hair, she finds herself slightly isolated from the popular crowd at school. Her daily routine revolves around her intense, lifelong bond with her neighbor Rune, which suffers a severe blow when his family relocates. Upon his return years later, she harbors a heavy secret regarding her health that she fears will cause him pain.

Rune is an intense teenager with a distinct talent for photography. Originally a hesitant immigrant, he finds early comfort in his vibrant neighbor Poppy, forming an inseparable attachment to her. After his father forces the family to relocate back to Oslo for two years, Rune returns to Georgia harboring a bitter attitude. He struggles with deep-seated anger over the forced separation and Poppy's sudden withdrawal of contact.

Erik is Rune's father, a working professional whose career dictates the family's international living situation. He uproots the family to Georgia and then back to Oslo, decisions that severely strain his relationship with his eldest son. Viewing teenage romance through a purely practical lens, he assumes Rune will easily move on from Poppy, inadvertently fueling years of resentment.

James is Poppy's father, a protective man who harbors reservations about Rune's brooding nature. He initially disapproves of the intense bond his daughter shares with her neighbor, viewing the relationship through the cautious lens of a typical parent. He seeks to shield Poppy from emotional harm during her high school years.

Adelis is Rune's mother, a caring figure who frequently attempts to mediate the growing hostility between her husband and her oldest son. She tries to offer comfort during Rune's periods of intense isolation but remains aligned with Erik's decisions regarding their living arrangements.

Ivy is Poppy's mother, defined by her deep dedication to her children's well-being. She maintains a polite relationship with the neighboring Kristiansen family but shares some of her husband's quiet concerns regarding Rune's dark mood upon his return from Oslo.

Alton is Rune's younger brother. Much younger than Rune, Alton idolizes his older sibling and desperately seeks his attention. He often finds himself ignored as Rune withdraws into isolation and anger following the family's relocations.

Savannah is the middle Litchfield sister. She possesses a somewhat withdrawn and sensitive demeanor compared to her siblings. She reacts strongly to the emotional shifts within her household and looks to her family for stability during turbulent times.

Ida is the youngest of the Litchfield sisters. She shares Poppy's physical appearance and natural cheerfulness, often looking up to her older sister's artistic pursuits and romantic milestones with awe and excitement.

Mamaw is Poppy's beloved grandmother and early childhood confidante. She imparts a philosophy of boundless optimism to her granddaughter, emphasizing the importance of "moonbeam hearts and sunshine smiles." She gifts Poppy a special jar meant to collect a thousand meaningful kisses, setting the foundation for Poppy's lifelong romantic outlook.

Deacon is one of Rune's few friends in Blossom Grove. He attempts to welcome Rune back into the local social scene after Rune's absence in Norway. He frequently organizes social gatherings and helps bridge the gap between Rune's brooding isolation and the rest of the high school community.

Judson is another of Rune's high school peers who helps facilitate local events. He co-hosts a welcome-back party for Rune in an attempt to pull him back into their friend group, though he sometimes misreads the underlying tension between Rune and Poppy.

Jorie is Poppy's supportive best friend at school. She provides Poppy with social updates and companionship, especially acting as a sounding board regarding Rune's unexpected return to town and the shifting dynamics among their classmates.

Avery is a popular student at the local high school who actively pursues Rune's attention. She serves as a source of deep discomfort for Poppy, relishing the apparent rift between the former couple upon Rune's return to Georgia.

Aunt DeeDee is Poppy's aunt, who works for an airline. She provides practical assistance and logistical support to the Litchfield family during stressful periods, occasionally clashing with Poppy's father over the best course of action for her niece.