Grace Pudel is a young girl navigating her childhood in 1970s Melbourne, Australia. She resides with her twin brother, Gilbert Pudel, and their French father, Percy, a former juggler who now faces life as a paraplegic battling an alcohol use disorder. Grace finds solace in her peculiar hobby of collecting snails, a passion she shares with her late mother, who tragically passed away during childbirth. The bond between the twins is both profound and protective; Gilbert fiercely defends Grace against the cruel jibes of their schoolmates, who cruelly mock her for her cleft lip, a consequence of her early arrival into the world.

Tragedy strikes when Percy dies unexpectedly in his sleep, leading to the devastating separation of the twins as they are sent off to different foster homes across the country. Grace finds herself in Canberra, under the care of Ian and Narelle, who, despite their kindness, are frequently absent due to their lifestyle choices as swingers. Meanwhile, Gilbert is placed with a family in Perth who adhere to strict religious fundamentalism, where he suffers severe mistreatment, particularly at the hands of the cruel matriarch, Ruth. Over the years, Gilbert clings to hope, writing letters to Grace promising their eventual reunion, while Grace, despite her longing, struggles to form connections or discover any passions. This leads her to obsessively acquire snail-themed collectibles, which becomes a symbol of her isolation.

As adolescence arrives, Grace forms an unlikely bond with Pinky, an eccentric yet warmhearted elderly woman. Pinky, despite her own misfortunes—having lost two husbands and numerous jobs—always maintains a perspective of finding silver linings in life. When Ian and Narelle decide to retire and join a nudist community, Pinky becomes Grace’s foster mother, steadfastly guiding her through the turbulent years of puberty, yet Grace remains trapped in her depression and a sense of directionlessness. All the while, Gilbert continues to endure torment from his foster family, except for the youngest son, Ben, who secretly admires Gilbert’s rebellious spirit.

As Grace transitions into adulthood, she falls deeply in love with Ken, a neighbor who works as a microwave repairman. Their relationship blossoms quickly, leading to Ken’s proposal; however, on the fateful day of their wedding, Grace receives heartbreaking news from Ruth—Gilbert has perished in a fire. In a fit of rage, Gilbert had ignited the fire after enduring electric shock punishment when Ruth discovered his relationship with Ben. This revelation devastates Grace, plunging her into a deeper melancholy evidenced by her excessive hoarding and overeating habits, compounded by the shock of discovering Ken’s hidden obsession with feeding her to fulfill a fetish for larger women, ultimately leading to their divorce. The only stable figure left in her life is Pinky, who continues to support Grace through these tumultuous times.

Time marches on, and Pinky is diagnosed with Alzheimer’s, flipping the caregiver dynamic as Grace assumes the role of caregiver. After several heart-wrenching months, Pinky passes away, leaving Grace bewildered by her cryptic last words concerning potatoes. In a moment of sorrow, Grace scatters Pinky’s ashes in her vegetable garden and liberates her cherished snail collection. Feeling utterly lost and hopeless, Grace contemplates suicide through poisoning, but she stumbles upon a box of savings left by Pinky hidden in the potato patch. Inside, a poignant letter from Pinky encourages Grace to move forward unburdened by the past. Inspired by her mentor’s words, Grace begins to purge her snail collection, preserving only a cherished beanie crafted by Percy.

Fast-forward a year, Grace has transformed her life, pursuing her dreams of becoming a stop-motion animator. During a screening celebrating her short film, a miracle occurs: Gilbert walks back into her life, having survived the blaze and braved the world to reconnect with her. Their tearful reunion rekindles their connection, allowing them to finally honor their father’s wish—scattering his ashes on a rollercoaster ride at Luna Park, the amusement park that once provided them joy during their childhood days. In this moment of reconciliation and hope, the twins rediscover their bond, ready to embrace a future filled with possibilities.