A young intern's first day at GCHQ coincides with a major cyberattack on the UK. To win her superiors' trust, she breaks ranks to analyse the malware code without permission and uncovers a greater threat missed by others.
Casts:
Hannah Khalique-Brown, Simon Pegg, Maisie Richardson-Sellers, Edward Holcroft, Adrian Lester, Alex Jennings, Hattie Morahan, Ed Stoppard