Catherine, featured in the "Clinical Chart 7: Black and White" episode of the Black Jack OVA, is engaged to Yasuhiko Shirabyoshi, chief of surgery at Tozai University. She requests a six-month wedding postponement to volunteer medical aid in Adentarl, a region gripped by civil war. En route to a refugee camp there, she encounters Black Jack, who searches for Karen Aramis, a girl suffering from the hereditary heart condition Tetralogy of Fallot. Catherine assists Black Jack during Karen's emergency surgery in a field hospital. After the operation, she departs via helicopter while Black Jack stays to treat other refugees.

Upon her return, Catherine attends an International Medical Association (IMA) panel concerning Black Jack's medical license. Dr. Stanfield advocates granting him an international license, asserting medical ability transcends conventional boundaries. Catherine's fiancé, Shirabyoshi, opposes this. Her presence stems from witnessing Black Jack's surgical skill and dedication firsthand. Catherine's actions demonstrate commitment to humanitarian medical work and a willingness to delay personal plans for professional ethics. Her testimony at the IMA panel underscores the conflict between institutional medical authority and unlicensed practitioners like Black Jack.