Yes, you are correct - the story must be sent as an attachment.  And, nothing is required in the body of the e-mail.  Just make sure to remember the format requirements below:

ELECTRONIC FILE – The Short Story must be sent as a .doc (Word document), .txt (Text File) or .rtf (Rich Text Format).  The name of the file must be as follows : “Your Heat Number”_“The Title of your Short Story”.  For example, if you were in Heat number 15 and the title of your Short Story was “Tennis”, then the name of your Short Story must be saved as “15_Tennis.doc” or “15_Tennis.txt”

FONT - Each individual Short Story must be typed in 12 point and in Courier, New Courier or Times New Roman typeface – ONLY.

TITLE PAGE -The Title Page of the Short Story must only contain the TITLE of the Short Story and the BRIEF SYNOPSIS.

BRIEF SYNOPSIS -The brief synopsis must be a maximum of 2 sentences and a minimum of 1 sentence (and no longer than one-half page in length). The brief synopsis serves as a description of the Short Story.

ANONYMITY - The author’s name must NOT appear anywhere in the Short Story, including the title page.

LENGTH - The maximum length for each individual Short Story is 2,500 words, not including the title page.

Hope this helps.  Thanks and good luck!