When Walter checks in at hospital for a near-routine checkup, Toby corrects a wrong diagnosis an thus discovers a mysterious blood virus epidemic, but also that the entire L.A. blood supply is compromised. Someone hacked the computer network to change the bar coding, using a code that can't be cracked timely to prevent many life-saving operations having to be canceled, including young Olivia's heart transplantation. The team tracks down the culprits and his motive, desperate for clues to guess the code. Time having run out for Olivia, they go the extra miles by speeding car.
—KGF Vissers