Leah Pearlman assisted Ryan when he came to her concerning his pregnant girlfriend, Valerie Stevens. Pearlman instructed Ryan to retrieve from the Mothership a vial of phosphorus, which was needed so Valerie can survive the pregnancy. Later, Ryan took Valerie to see Pearlman where she performed an ultrasound. Afterward, she told Ryan that the ultrasound image she showed Valerie was actually that of a healthy human woman's fetus. Pearlman showed Ryan what her actual ultrasound looked like. She went on the road with Ryan and Valerie to take care of the mother and the baby. When a Visitor Soldier came and abducted Val, Leah was knocked unconscious and was abandoned at the safe house. She went into hiding to avoid further targeting from the V's.