Rouge makes her debut by trying to steal the Master Emerald from Angel Island. Knuckles, the guardian of the Emerald, tries to stops her. In the midst of their arguing, Dr. Eggman arrives and steals the Emerald. To prevent the Master Emerald from falling into the wrong hands, Knuckles shatters the Emerald into pieces. After more bickering with Knuckles, Rouge leaves to collect some of the Master Emerald shards.
The area is in the desert close to Eggman's secret base, a pyramid, and there is a large amount of water in this stage. The lagoon is home to a lot of wild life including two giant Turtles. Rouge can rescue one from a pair of G.U.N. Hunter robots and use it to get to the other part of the stage by riding on its back, while the other can be used to get to the Oasis Prison.
These ruins have a mysterious wind cycle and secret walls to dig through once Rouge discovers the Level Up Item Pick Nails.
Find three pieces of the Master Emerald
The pieces of the Master Emerald are placed in different random locations each time the player plays. To find them, use the radar at the bottom of screen. As you get closer, it turns green to yellow to red and the "ping" sound speeds up. The player can also references the Hint Box for hints, but doing so subtracts points from the score (making it more difficult to get A Rank).
Collect 100 Rings
This is one of the easiest missions in the game. There are more than enough rings in the first area, so do not bother using the Turtle. The various ledges and airspace around the tall, dark pillar are especially lucrative.
Find the Lost Chao (Iron Boots, Pick Nails and Mystic Melody required)
Breaking the Iron containers along the southern wall of the top floor reveals a painting. Dig into it, and the player lands in a room containing an ancient shrine and a door. Play the melody near the shrine to open the door. Walk through it, jump into the blue swirl, and the player is transported to the Lost Chao's location.
Get the Emerald pieces in 3:30
Because this stage is not very large, completing this mission should not be too much a problem. Do a quick sweep of the area you start in, and if nothing shows up on the radar, liberate the Turtle and transport to the Big Oasis area.
Clear Hard mode (Treasure Scope required)
In hard mode, the pieces of the Master Emerald are always in the same place. To reach the first piece, begin by destroying the wooden crate on the second ledge above the starting point. Launch from the exposed Spring, and at the height of the bounce, glide forward to grab the Emerald.
For piece two, climb into the large picture on the east wall, and dig into the cross bar of the scale. A hidden Spring launches the player into the Emerald. The final piece is located in the Big Oasis area. Take a ride on the turtle, turn on the Treasure Scope, and drop into the water (don't jump, just fall in). Look on the underside of the floating center island and the player will see a spring the player can bounce off of to snatch the last piece.