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.