After completing Tressa’s first chapter, return to Rippletide and you will find Le Mann on the docks towards the northwestern corner of the village. He speaks of going out on a grand adventure, but he not very equipped for it. In order to complete this Side Story, you will need either Tressa or Therion. Head to the stalls in front of the docks and look for an Antique Dealer, then either Purchase/Steal the Adventurer’s Attire from him and bring it back to Le Mann to finish.