The only female guide west of Tanganyika (and, according to Robert Muldoon, the best), Sonya was hired by BioSyn to investigate the strange occurrences on Isla Nublar. She and her partner, Raul Lopez, encounter Drs Alan Grant and Ellie Sattler, Edgar Prather and Muldoon on Nublar, and though there is an initial argument, multiple attacks (from a flock of Cearadactyls, which results in Sonya being handed a gun by Alan; and then by the army forces on the island) result in the two groups deciding to make a temporary alliance. Later, the group is attacked by the island’s Tyrannosaurus; it picks Sonya up in its mouth, but a shot from Alan makes it drop her, and Edgar tends to her wounds. The two then go off to talk, and Edgar kisses her – although she tries to resists, she eventually gives in. After this, the group sails across a river, and are attacked again by the Rex; upon landing, they come across the army’s base. Sonya decides to go with Edgar to the base; Edgar grapples up a fence and into a guard outpost, and then helps Sonya up. Sonya acts as a guard, letting the others escape, though not before noticing something; she then joins them as they flee in a jeep. At dawn, Ellie and Sonya talk; when Ellie asks her about her and Edgar, Sonya replies that it’s “just what you see”. When a Rex attack splits the group up, Edgar asks Sonya what the secret of the “Green Flame” is – when she refuses to answer, he knocks her over a cliff and leaves her hanging there until she talks. When she does, he drops her anyway.