MI-13 is the latest in a long line of British intelligence agencies dealing with "weird happenings" within the United Kingdom. It followed the likes of Special Tactical Reserve for International Key Emergencies (S.T.R.I.K.E.), Resource Control Executive (R.C.X.), Department of Unknown and Covert Knowledge (D.U.C.K.), and the Weird Happenings Organisation (W.H.O.).

It evolved from the remnants of W.H.O and now holds under it all paranormal organisations and has rationalise them into a single department as of August 1988. It often clashes with other intelligence agencies, including MI6 who wish to have jurisdiction over "weird happenings" and believe all the specialist groups like MI-13 are doomed to fail.