Seasonfourofespionagedrama"MI-5"findstheteamreelingfromthelossofDanny(DavidOyelowo),butthrownbackintoactionwhenabombdetonatesnearhisfuneral.ZafarYounis(
Raza Jaffrey )andJulietShaw(AnnaChancellor)areintroducedtotheshow,inastoryinvolvingapotentiallydevastatingterroristattackinthecapital.LaterintheseasonLyndsayDuncangueststarsasaformerMI-5officerwithadeadlygrudge,onewhichthreatensthelivesofeveryonebackatTheGrid.