BIONICLE #15: Secrets and Shadows is the fifteenth issue of the BIONICLE comic series.
The inside front cover provides brief backstory. The centerfold features information about the new Metru Nui Matoran sets and Kanoka disks. A back page advertises the movie BIONICLE: Mask of Light with a $2 coupon for the DVD. Another back page advertises the shadow kraata collectibles included in Rahkshi sets sold at Target in December. Another back page advertises the Toa Nuva-themed electric toothbrushes from Colgate. The back cover features a teaser for February 2004 with a silhouette of Toa Metru Vakama and the message "Are you ready to enter the city of legends?"