Go to Lakehaven Heights, your goal is Galahad Ruins it’s located on the northwest. There is a giant boulder blocked the northwest path, so you need circle around through the Northeast path.
Warning: You may find tough enemy along the path (purple wolf; IIRC, its name is Magnamr), avoid it if you see it. It probably kill you within 10 seconds :).
Use Silver Flame (up button) on purple mist which block your path.
The items found in the dungeon may different from yours (unless it’s a locked chest).
T2= Rosemary (Herb)
T3 = locked
T4 & 5 = Amber Garment & Earth Ring
T6 = Apple Gel
T7= Saffron (Herb)
T9 = Devil Wings
M is short for Monolith, visit THIS PAGE for more info about it.
Go to point S1 on this dungeon, you will see a bow and familiar clothes :). Once the event ends, go back to the bow and check it one more time to find a discovery point (Altar of the Bow).
Now simply continue to S2 to trigger an event and a battle. The battle is very easy. After you win go to S3 and then check the water to end this chapter.