Lock-On

Ensures that the user's next move will hit the target.

Lock-On allows the user's next move to bypass any accuracy and evasion checks to guarantee a hit.
This even includes the semi-invulnerable turn of moves such as Dig and Fly.
However, this does not prevent moves boosted by Lock-On from failing for other reasons such as hitting a hitting a target protected by Protect.
The damaging turn of Future Sight and Doom Desire already count as the next move.
The effect lasts until the end of the next turn regardless of what move is used or if either target or user leave battle.
Lock-On can not be transferred to an incoming Pokémon through Baton Pass
Lock-On fails if the target is behind a Substitute.

• In Gen 2 the effect lasts until the next move against the target of Lock-On
  Lock-On is a status attached to the target in this generation meaning that allies of the user can also receive the 100% hit guarantee.
  The effect ends if the affected target leaves.
  The effect also does not allow the moves Earthquake, Fissure or Magnitude to hit a Pokémon in the semi-invulnerable turn of Fly.
  In that case the move misses and the effect of Lock-On ends.
• In Gen 2-3 Lock-On has 100% accuracy
• In Gen 2-4 Lock-On does not fail if the effect is already active.
• In Gen 3-4 only one Pokémon at a time can have apply Lock-On or Mind Reader to a target.
  If another Pokémon uses one of these effects on the same target, the previous move will be overwritten.