Henry Garrison

Henry Garrison is a prisoner in the Innsmouth's Jailhouse.

Role in the game
Garrison is located in the cell next to the cell where Brian Burnham is locked up on one side and the cell where Thomas Waite was imprisoned prior to his suicide. Right from the start it is clear that Garrison isn't a sane person, constantly mumbling nonsensical words, making guttural noises and most notably speaking about "rats in the walls".

Despite his craziness, Jack can exploit his mental state to his advantage. For instance, as told by Burnham, whenever someone walks through the back alley of the Jailhouse, Garrison will start screaming which for some reason always alerts the policemen Ropes and Birch. Interacting with Garrison or just standing for a bit near the window will trigger this reaction and Ropes will exit the Jailhouse to investigate, allowing Jack to kill him from the back using a crowbar or to sneak inside the Jailhouse.

During the sequence when Jack and Brian walk through the sewage tunnels, it is possible to stumble upon dead rats which can be taken and given to Garrison. Showing to him that rats are dead and that they aren't inside the walls will trigger Garrison to go completely crazy and he will start smashing his head into the cell door, killing himself.

Alongside his dead body is an old paper, The Oaths of Dagon.

Trivia

 * Garrison's "rats in the walls" is an easter egg to the famous novel by H. P. Lovecraft called "The Rats in the Walls"
 * The ultimate reason for Garrison's imprisonment is unknown, although it is likely that he refused to take the Third Oath of Dagon and thus gone mad in the process
 * It is implied that if he survived he would have been sacrificed to Father Dagon
 * Henry Garrison is a reference to one of the boys that dissappeared in connection to the sacrifices made by captain Obed to the Mysterious Deep Ones in the story by H.P. Lovecraft "a shadow over innsmouth".