Sara Goodman, known as Sora Yamato in Japanese, is a human middle school student living in 25th-century Tama City, Japan, aged between 12 and 15. She possesses long pink hair, blue eyes, and favors a practical outfit: a long-sleeved yellow top, blue trousers with multiple pockets, brown shoes, and suspenders, often accessorized with pink bracelets on her left wrist.

As Tony Goodman's (Tokio Yamato) fraternal twin and Dr. Bernard Goodman's niece, Sara displays stronger academic abilities than her brother and worries about his school performance. Their close sibling bond is demonstrated when Tony identifies the real Sara among clones created by Shadow. While initially stating no significant future plans, Sara later aspires to become a Time Detective alongside Tony, acknowledging they both had "too many things to do."

Sara generally avoids conflict and violence, preferring peaceful solutions and showing empathy. She fought only once under the influence of Time-Shifter Muscles, quickly transferring control to Genshi due to discomfort. She also felt deep embarrassment wearing a bunny-girl costume to maintain modesty after a size-changing incident. A significant personal development saw her overcome a lifelong fear of insects during an encounter in Episode 30, stemming from a childhood trauma when Tony dropped a bug on her.

She actively supports Time Detective missions, often providing food to sustain Flint Hammerhead's energy. Sara discovered the fossils of Flint and Ototan on an archaeological field trip, enabling their de-fossilization. She assumes a nurturing role towards Genshi while maintaining professional respect for Merlock Holmes (Kyoichiro Narugami), a vampire-descended Time Detective who frequently assists her; his persistent romantic attentions receive no reciprocal interest.

Muscles temporarily transformed Sara into a giant, an effect later reversed by Getalong. Her character arc culminates in the series finale with her declaration to pursue a Time Detective career, aligning with Tony's ambitions.