Appendix:Red and Blue walkthrough/Section 17

This is the Bulbapedia walkthrough for Pokémon Red and Blue.
These pages follow the original Game Boy iteration, not FireRed and LeafGreen. The guide for those games can be found here.

Cerulean City

There is only one place left to explore: Cerulean Cave, a mysterious place on the northwest edge of Cerulean City. To get there, visitors must Surf southward from Route 24.

Cerulean Cave

Cerulean Cave, 1F
Cerulean Cave, 2F
Cerulean Cave, B1F

Cerulean Cave is a mysterious cavern located in the northwest part of Cerulean City. Only the most powerful Trainers who have entered the Hall of Fame are allowed to enter due to the powerful wild Pokémon inside. The sprawling cave network is unforgiving, so be sure to prepare well. Pack the Super Rod and stock up on Ultra Balls, and bring the Master Ball as well. It is here that the genetically-engineered Pokémon from Cinnabar Island's Pokémon Mansion fled after escaping the facility.


Walk up onto the rocky ridge and climb up the ladder to the second floor.


Loop around to the east, grab the PP Up, and take the ladder in the northeast corner back down to the first floor.


Go down the stairway and use Surf to swim westward. Grab the nearby Max Elixer and climb onto the rocky ridge to the northwest. Grab the Nugget and climb up the ladder.


Head east through the maze to find a Full Restore, then continue on to find the next ladder.


Go west and surf across the water for another Full Restore, then climb back onto the central rocky ridge. Follow the southern tunnel to the next ladder on the western ridge.


Pick up the Ultra Ball, then follow the winding trail to the ladder in the northwest corner.


Take the next ladder down to the lower floor.


Head northeast from the ladder and grab the Max Revive from the smaller rocky ridge. Turn around and follow the tunnel to the southwest, then climb up onto the central ridge to reach another Ultra Ball. Use Surf to swim along the water and cut across the rocky ridge in the northeast. Surf southward to find Mewtwo, alone on its island. Be sure to save the game before interacting with it, as there is only one chance to catch it.

VS Mewtwo

Not only is Mewtwo the strongest Pokémon around, but it has already reached level 70. As a Psychic-type Pokémon, it is only vulnerable to Bug-type attacks. Bug moves are fairly weak, and so a better way would be to use the Legendary birds, as they are the closest to Mewtwo's equals in terms of power. The Legendary Pokémon can restore its health repeatedly with Recover, so inflicting status ailments are a must. Not only will this make Mewtwo easier to catch, but Sleep, Freezing, and Paralysis will prevent it from replenishing its HP. It will not let itself be caught easily, so either use the Master Ball when the battle begins or be prepared to go through more than a few Ultra Balls.

Psychic Unknown
Mewtwo Lv.70

With the Pokémon League defeated and Cerulean Cave cleared, the only thing left to do is to complete the Pokédex. There are 151 different Pokémon species that have been discovered so far, leaving plenty of training left to do!

← Part 16 The Pokémon League
Red and Blue

  This article is part of Project Walkthroughs, a Bulbapedia project that aims to write comprehensive step-by-step guides on each Pokémon game.