Ambush is the 40th episode of Bakugan: New Vestroia. It aired on January 27, 2010.
As Dan and the Brawlers continue their search for the Bakugan Termination System, they run into an ambush, by the Palace Guards. The Brawlers (minus Dan and Mira) are forced to separate, and wind up engaging in their own battles with the Vexos. Unbeknownst to them, the Vexos have rigged it so that it is impossible for them to lose when fighting with Mechanical Bakugan inside the Palace. In the end, the Vexos take the Ventus and Darkus Attribute Energies, (in the brawls between Shun and Baron against Mylene and Volt, and Marucho and Ace versus Lync and Shadow) leaving only the Pyrus to be collected in order for the BT System to be fully operational. As Dan and Mira stumble upon Hydron, the rest of the Brawlers race around trying to find them in order to warn them about the trap set by Zenoheld and the Vexos. Finally, Spectra presents a proposition of the Phantom Data to Dr. Clay.
- The Resistance enters the palace and split into pairs.
- Shun and Baron are transported to an arena where they are forced to battle Mylene and Volt.
- Marucho and Ace are transported to an identical arena where they are forced to battle Lync and Shadow.
- The battle arenas are revealed to be rigged so that Mechanical Bakugan cannot lose.
- Marucho and Ace lose their battle, with Percival losing the Darkus energy.
- Shun and Baron lose their battle, with Ingram losing the Ventus energy.
- Dan and Mira are transported to one of the trap arenas and come face-to-face with Hydron.
- Spectra shows Professor Clay the phantom data he received.
- Unlike the other episodes when only one Attribute Energy was taken, this is the only episode where two Attribute Energies were taken - Ventus and Darkus.
- This is the first of only two episodes that have the same title across Japanese and English versions, the other is Ultimate Weapon.