Three of stockholm's top business executives have been brutally murdered in as many days and that's only the beginning. Cid inspector jenny hultin is assigned the task of quickly putting together a special team of police officers to apprehend the fat cat killer .this leads to the creation of the a group, a group of six carefully selected police officers with varied backgrounds from all over the country. The cases that the a group handles are high priority threats involving particularly complex and dangerous violent crimes with a direct or indirect international connection.the hunt for murderers and psychopaths puts a heavy strain on relationships within the group, as well as on the members' private lives, which prove to harbour unexpected secrets sometimes with a disturbing connection to their work.