2. Go back to the Dragonspiral Tower.
3. Climb the tower to the top.
4. Battle Zekrom.
Here are some additional tips for re-battling Zekrom:
* Zekrom is a powerful Dragon/Electric-type Pokémon. Be prepared with strong Water, Ground, Ice, or Rock-type Pokémon.
* Zekrom can use the move Fusion Bolt, which hits all adjacent opponents. Be sure to spread your Pokémon out so that they don't all get hit by this move.
* Zekrom can also use the move Outrage, which increases its Attack stat by one stage each time it hits. Be sure to take Zekrom down quickly so that it doesn't get too many boosts to its Attack stat.
* If you have a Pokémon with the ability Sturdy, you can use this ability to protect yourself from Zekrom's Outrage move.
* If you have a Pokémon with the ability Levitate, you can use this ability to avoid Zekrom's Ground-type moves.