Sienna Marchione, an engineer, interrupts a breakin at Heptagon Labs, during which military-grade technology was stolen.She takes down two of the intruders. The technology makes people and weapons invisible. Sam is trying to locate some SEAL pins he lent to Hetty. He wants to give one to Kam at her graduation. Nell agrees to look for it. Kensi and Deeks go to speak with Sienna. But she isn't aware of them because she's back to them and deaf. Sienna wants to serve her country but she can't enlist because of her deafness. Owen, one of her engineers, called in sick the previous day. Kensi recruits Sienna for that case. Deeks and Nell don't want that to happen. But Kilbride overrules and brings Sienna aboard. Kensi, Fatima, and Sienna go to question Owen. Deeks helps out Nell. Fatima tries signing for Sienna. Owen is sick from food poisoning. Sam and Callen are fired upon by the third robber and Sam gets winged. Sam shoots the gunman in the leg but another man rescues him and they escape. Kilbride got an earful from SecNav. Sienna smelled ipecac syrup at Owen's house. Kilbride gives Nell some tough love. Fatima tails Owen. Saudi Ehsan Rahman owns the club where the robber was hiding out. Owen meets with Rahman and gives him the keychain to the drive. Owen had $3 million deposited into his account. Fatima arrests Owen but Rahman escapes before Sam and Callen arrive. Sam and Callen chase down Rahman'a vehicle at a private airstrip. Kensi cuts Rahman off before he reaches the plane. Nell finds the pins hidden in Hetty's liquor cabinet and arranges for a private jet for Sam and Callen to fly to the graduation. Kilbride reflects about the military having no place for someone as talented as Sienna.