Writer:	Adam Peltzman
Director:	Koyalee Chanda
Star:	Cheryl Blaylock (Frederica (Blue's Room)),  Traci Paige Johnson (Blue),  Donovan Patton (Joe Burns (Season 5+)),  Jonathan Press (Shovel (Seasons 4-5)),  Marshall Claffy (Pail (Seasons 1-3)),  Aleisha Allen (Side Table Drawer (Sometimes as Aleisha L. Allen, LaNaé Allen in Season 3+)),  Nicole Gibson (Pail (Season 6)),  Seth O'Hickory (Mailbox),  Nick Balaban (I) (Mr. Salt),  Stephen Schmidt (III) (Shovel (Seasons 1-3)),  Victoria Pontecorvo (Puppet Blue (Season 6)),  Cody Ross Pitts (Slippery (Seasons 1-3)),  Kathryn Avery (Tickety Tock (Seasons 1-3)),  Kelly Nigh (Tickety Tock (Season 4+)),  Patrick Van Wagenen (Slippery (Seasons 4-5)),  Julia Wetherell (Pail (Seasons 4-5)),  Spencer Kayden (Mrs. Pepper),  Sean Hanley (III) (Slippery (Season 6)),  Christiana Anbri (Moona (Blue's Room)),  Thomas Sharkey (Shovel (Credited as Tom Sharkey, Season 6))
Recurring Role:	Steve Burns (Himself (Seasons 1-4)),  Cameron Bowen (Periwinkle),  Brittany Famighetti (Steve's Friend)
Guest Star:	Ralph DiPasquale (Steve's Friend),  Dorothey Jane Washington Green (Steve's Friend),  Kenny Kim (II) (Steve's Friend),  Jesse Regina (Steve's Friend),  Nicky Regina (Steve's Friend),  Valerie Cosgriff (Steve's Friend)

In this episode, Blue doesn't know the answer to Blue's Clues anymore than Steve or us do. Additionally, the clues just seem to appear without Blue ever placing her pawprint on them. Finally, there is no Blue Skidoo segment in this episode. (edit) "Blue's Big Mystery" is the first of two episodes on the video "Playtime With Periwinkle." The video includes several promos for various Nickelodeon productions at the beginning as well as segments featuring Nick Jr.'s Face mascot and the Nick Jr. kids. (edit) Nicky Regina is credited as Nicholas Regina. Catherine Mullally, Maggie McGuire and Beth Mayerowitz all receive Special Thanks credits. (edit) This episode introduces the character of Periwinkle, as voiced by Cameron Bowen. At first he is credited as one of "Steve's Friends," but is soon added to the list of cast credited along with the name of their character. Towards the end of the fourth season/start of fifth season, Cameron Bowen is replaced by Kenny Kim as the voice of Periwinkle. (edit) Mailtime Segment: Mailbox pops in wearing a detective outfit and provides a mystery letter. It turns out to contain a leaf. There is no video letter. (edit)

Steve: What's your name?
Kitten: What's your name? (edit) Steve: Follow that clue! (edit) Steve: The mystery builder has struck again. (edit) Steve: You know, this clue is kind of like evidence. What part of the body makes footprints? (edit) Steve: Are you the mystery builder?
Kid: Nope. (edit)

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