When the Dragon Caesar and Daizyujin got covered in foam, they had sent the ZyuRanger to the Lapless Room because the foam was too much for them. Once there, Klotho gave them a hint to head North and to look for a river. Once there, Geki had located an Ancient Artfiact which after 1 of them read the language on it, it was discovered to be the key to unlocking the Ultimate Daizyujin which is the ZyuRanger name for the Ultrazord. The key to unlocking the power was they each had to state their trait and then place their Medal/Coin into the slot on the Artifact. Mei was the first one who mentioned her trait which was "Love" and she inserted her Coin onto the Artifact as shown here. Next was Boi whose trait is Hope. Here's his Coin as shown on the Artifact. Next is Goushi whose trait is Wisdom and here's his Coin as shown on the artifact once he places it on the artifact. Next is Dan and his trait is Courage. Here's the shot of his Coin on the Artifact. Burai's trait is Power (shot of Coin on Artfiact is here and Geki's trait is Justice and here's the shot of his Coin on the Artifact. Here's thes full shot of the Artifact with all 6 Coins on it.
This episode features the first appearance of the MegaDragonzord along with the first appearance of its cockpit and this is actually the only time in which all 6 Rangers are in the cockpit.
This is also the first appearance of the Ultrazord.