Tamzin Merchant and David O'Hara also aboard the supernatural thrillerWhile he waits to see whether the Mortal Instruments series gets back on its feet for City Of Ashes, Robert Sheehan is hopping aboard a film that also features supernatural themes, albeit with a more naturalistic style. He’ll be part of The Messenger alongside Lily Cole, Jack Fox, David O’Hara and Tamzin Merchant.David Blair is set to start cranking the cameras this week in the UK, working from Andrew Kirk’s script.