The discovery of a drowned sailor in dress whites, with an officer's ceremonal sword and weights chained to his waist, sparks a suicide investigation. Kate refuses to believe the deceased committed suicide, as he came from a Catholic family. Abby discovers a link between the crew of the USS Foster and an MMORPG known as 'The Immortals', and searches the game for clues and evidence in order to assist Gibbs in resolving the case.