The fourth season of the groundbreaking cybersecurity drama series finds Mark and his new family at 'Good Shepherd Cybersecurity' reaping the rewards for their hard work and brilliance. There's a smart new office and a team of enthusiastic new colleagues to help them. Mark, AJ, Fiona and Maurice are called in when a major international energy company is targeted by a terrifying ransomware attack. Mark is still intent on dragging Charlotte away from the dark side His sister Violet makes a return to the fold to deploy her unique skills in a high profile project. Question is, who is the evil mastermind behind this next level threat and how will the team respond? Seeking the answer will take Mark and friends on a journey that will test their loyalties and technical capabilities beyond anything they have previously encountered.