|Into the Mouth of Darkness|
|Original broadcast||December 5th, 2009|
|Series||The Secret Saturdays|
|Overall episode number||30|
|Written by||Ross Beeley|
|Directed by||Scott Jeralds|
|Previous episode||The Thousand Eyes of Ahuizotl|
|Next episode||The Legion of Garuda|
The Saturdays set a course for Greenland so they can search for an ancient Sumerian tablet, but are forced to take a detour to Australia when the airship gets infested by Bunyip cryptids. Zak finds himself having to keep the secret of his alliance with Argost, while also fighting along side his parents to keep up the charade and locate the monster of the abandoned mine. Leaving the rest of his family in the dust, Zak confronts Argost alone. Realizing from Argost that he was the monster the cryptids were fearing and that his powers had started to corrupt him, Zak lets him escape and hides this revelation from his parents. Meanwhile, Doyle and Van Rook track down Baron Finster in order to uncover the secrets of Argost's past. The duo learns that Argost wasn't always how he currently was: he used to be a completely penniless man.
- Doc Saturday
- Drew Saturday
- Zak Saturday
- Doyle Blackwell
- Fiskerton Saturday
- Komodo Saturday
- Zon Saturday
- Van Rook
- Kur (a.k.a. Zak Saturday)
- Fiskerton Phantom
- Komodo Dragon
- Yeti (a.k.a. V.V. Argost)
- Algerian Sea Centipede
- The chase scene in the silver mine is similar to the one from Indiana Jones and the Temple of Doom.
- The meaning of this episode is explained when Argost tells Zak of how much of a monster he has become with the Bunyips being scared of him. This means that Zak is going deeper and deeper into the darkness, which means the bad side and also down the path of evil.
- This episode showing what Zak is becoming is similar to Star Wars: Episode II - Attack of the Clones. Anakin Skywalker also had conflict that brought him into the darkness.
- Zak/Kur is the real monster of this episode.
- This episode is called "Into the Mouth of Darkness" because, like Argost said, Zak has in fact become some sort of monster. One, the Bunyips are really scared of him (they even have sad puppy dog-like faces with a few tears). Two, he lies to his parents, betrays his own mother, and lets the bad guy get away.
- This marks the end of Zak's deal with Argost when he says that he needs to stop listening to that guy.
- It is ironic that none of the Saturday members found the Bunyips to be cute, since after all, that was the purpose of the way they were drawn.