The accidental discovery by an archaeologist in Almeria of an ancient manuscript that turns out to be a formula for a virulent poison, much deadlier than The Black Death or The Spanish Lady, brings together a group of people who have a grudge against the Establishment and are not averse to use what they have found for fiscal benefit. After deciphering the hieroglyphics the group produce a small sample of the poison and after successfully testing it on small communities in Mexico and France try to blackmail the British Government, but they are dismissed as harmless cranks. This forces the group to enter into a partnership with others who unbeknown to them have a secret agenda, which is to sell the formulae, known, as The Indalo because of where it was found, to the highest bidder on the open market. These people do not need the others and anybody who knew of its existence are systematically eliminated by Angel, a trained assassin who was an ex-operative of The Firm, a clandestine Government Department that specialises in all the things that others refuse to do on ethical grounds. An e-mail message from the grave of one of the original group to Paula Marshall, also an ex-agent from The Firm, spirals her into a world she thought had been left far behind, leading her into a race against time to locate a second manuscript believed to be in existence which hopefully contains the antidote, and to stop the sale of the formula. In doing so it brings her into contact with people from her past and makes her rediscover herself along the way, finding that things aren't always as they appear and people often lead strange deadly double lives.