London1864.OnaHackneyboundtrainaguarddiscoversbloodinafirstclasscarriage-andabodyontherailwayembankment.ForthefirsttimeamurderhastakenplaceonBritain’srailways.OverahundredyearslaterthissingledocumentaryforBBCTwousesthefirsthandtestimonyofthepeopleinvolvedatthetimetoexplorethisuniqueeventandhowitprovokedahugepublicoutcryanddebate.Thestoryquicklybecameanewssensationasthedangersofthebravenewworldofthetrainwerelaidbare.Overahundredyearslaterthewitnessestothisstorymaybelongdeadbuttheirwordssurviveincourttranscriptsmemoirslettersandvividjournalism.Thesetestimoniesarenowusedtotellthestorytakingthedocumentarydeepintothenineteenthcenturytomeetanextraordinarycrosssectionofreal-lifeVictorianLondon-fromtheenginedriverwhofoundthebodytothedetectiveinchargeoftheinvestigation.WhokilledMrBriggs?