When a mysterious lawyer (Thekla Reuten, In Bruges) asks solicitor Harry Venn (Philip Glenister, Life on Mars, The Level) to find a missing alibi witness for her client, he's forced to delve back into his murky past and uncover a far-reaching conspiracy in this "intelligent, pacy TV thriller" (The Telegraph) that also stars David Suchet (Poirot) and Richard Dormer (Fortitude, Game of Thrones).