Doctor Who: Assassin in the Limelight

Ford's Theatre, Washington. Friday, 14th April, 1865. The assassination of Abraham Lincoln. The place, the date and the event which made history. Or did it? Someone has been tampering with time, muddying the waters of history for his own purposes. Time itself is out of joint and the chief culprit is the enigmatic Doctor Knox. Somehow the Doctor and Evelyn must put history back on track before the future dissolves into chaos. But Knox, it turns out, may be the least of their worries...