The Computer Club challenges the S.O.S Brigade to a contest for control of the club room, the contest being a multi-player space battle video game named "The Day of Sagittarius".; In his frantic search for answers, Kyon stumbles across a Mikuru who has no knowledge of him, a Yuki who is a shy, very human bookworm, and no trace of the S.O.S Brigade or that Haruhi ever existed.; Haruhi ropes the club into a Christmas party she's throwing and that forces Kyon to miss a double date a friend of his tried to set up.; During the video game battle, Yuki begins imputing commands on her keyboard at an inhumanly rapid pace and Kyon fears that she will be exposed as an android assigned to supervise Haruhi.; Kyon goes to school only to find Haruhi and the other members of the S.O.S. Brigade have disappeared and no one remembers them.; As revenge for losing to Haruhi's S.O.S. Brigade, the Computer Club begins trying to lure away the Brigade's members.; Series of humorous incidents revolving around the antics of Haruhi and the S.O.S. Brigade.