You’ll get TM57 Charge Beam from an NPC located at the beginning of Route 7, which is just north of Mistralton City. But before you’re able to reach Route 7 you’ll first need to defeat the Gym in Driftveil City and make your way through Chargestone Cave.
As for the move itself:
Charge Beam is all-around a poor move. Its base Power of 50 is far too weak, and even misses 10% of the time due to its 90 Accuracy rating. Charge Beam does have a chance to raise the user’s Special Attack by one stage, but only 70% of the time.
TM57 Charge Beam Location (Step-by-Step)
Step 1: Starting at the Pokémon Center in Mistralton City, head north onto the path behind the Center.
Step 2: Then turn and head east on the path behind the Pokémon Center towards the city’s exit.
Step 3: Follow the path east, then turn north to reach Route 7.
Step 4: Now on Route 7, head northwest and climb the small set of stairs to your left.
Step 5: From the top of the stairs, follow the path west. Then speak to the NPC with black hair pacing back and forth.
Step 6: After some brief dialogue, the NPC will give you TM57 Charge Beam.
Charge Beam Details + Uses
|Charge Beam Move Details
Charge Beam is a Special Electric-type move that is better left unused & ignored in most playthroughs.
It has poor damage, less-than-perfect Accuracy, and a secondary effect that leaves a lot to be desired.
The attack would be much more viable if it guaranteed the user a one stage increase in Special Attack – but this effect only happens 70% of the time.
A Status move like Calm Mind or Nasty Plot is much more useful and is guaranteed to boost your Special Attack.
Special Attack, like other stats, is increased or decreased by stage. The chart below details how Special Attack is increased by stage:
If Charge Beam was available in the early game, it would be a much more viable attack for the earlier portions of your playthrough.
But there are many better moves available before reaching Route 7 in Black & White – so generally this TM is not worth getting.