The first chamber is the only part of Mt. Silver that is dark enough to require the use of Flash. Grab the X Accuracy on the southeast platform, then loop around to the west to reach an Escape Rope. West of the middle platform between the ledges is a Dire Hit hidden on the rock. The northern, largest platform opens into a T-intersection; turn left to get a Max Elixer, then go right and south to find a hidden Ultra Ball. Head back north to reach the opening in the northeast.
Surf out into the lake, climb the waterfall, and enter the small chamber to find a Max Revive. After that, go north to climb up a triple stairway. Climb the northeast waterfall to reach another small chamber with a Full Restore. Swim back across the lake and enter the opening to the north.
Cross the land bridge to meet the strongest opponent in the game, former Champion Red. His is the highest-leveled team of any Trainer, ranging from 73 to 81. To stand a chance against him, it is advisable to raise a team to about level 75. Even with a type advantage, Red's Pokémon won't go down without a fight.
Defeated, he pauses for a second in stunned silence. Then in the blink of an eye, Red is gone. It is possible to battle him again, by defeating the Elite Four again and returning to the mountaintop. A moment later, the credits roll for the second time but the game is not saved automatically - you will resume your adventure just outside the Pokémon Center next to Mt. Silver.
Having scaled Mt. Silver and defeated the legendary Trainer, the only thing left to do is to complete the Pokédex. Pokémon Gold and Silver brought the total number of Pokémon up to 251, so there is plenty of training left to do!