In FusionFall, Numbuh Three is lost in The Future when Fuse's forces nearly conquer Earth. In the Past, she's at Mount Blackhead with Numbuh Four, Coco, Mac, and Ed. She wonders about Mandy's cold personality and thinks she needs a hug. Her sweet personality has easily made her friends with Bubbles, in which Numbuh 3 helps mend the injuries of Bubbles' squirrel, Bullet, during Squirrel Squad; she then directs the player to the local Infected Zone to investigate the culprit of the attack on Bullet. When the player heads for Monkey Mountain to complete the Numbuh Three Nano mission, she asks for the player's aid in saving a family of Rainbow Monkeys, including Baby Monkey, who was in the possession of Fusion Numbuh 3.
- She and Numbuh Five are the only ones from the KND whose Nano types aren't the same colors as their sweaters.
- In Numbuh Three's Nano mission, Numbuh Three tells the player to "Defeat Fusion Juniper Lee," when actually the player will be fighting Fusion Numbuh Three.