If you wield two weapons with the Light attribute, once a turn you may use 1 AP to make a Melee Attack with the offhand weapon. The offhand weapon only deals its own damage, no modifiers apply. 

Example: Syd, the assassin carries a Dagger +1 in each hand. She Attacks with her main hand for 2 AP and deals 1d4 + 1 + DEX damage. She uses her last AP to make an Offhand Attack. It deals 1d4 + 1 damage. The next turn she uses 1 AP to finish off the enemy with an Offhand Attack and moves for 2 AP towards the next enemy.