Lyric discussion by screed 

Cover art for Gethsemane lyrics by Richard Thompson

"Gethsemane" is the garden where Christ was betrayed. The song is about starting off with high hopes and being remorselessly ground down by life until you're a shambling old man with a brain tumour wondering what the hell happened. In the song, Gethsemane is the name of a fictional everytown and Cadie is a fictional body of water, so the setting is wherever you want it to be.