After helping Philia upgrade her weapon, she now asks you out for a treasure hunt.
Follow the path to fight your first NM monster inside Church for Two to Meet.
You can attempt to grab the two locked chests at Fertile Woods with Buzzing Bees if you have unlocked the PFT style. The PFT style is needed for 100% accuracy for you to kill the bosses. The locked chests offer you spear weapons.
The locked chest in Graveyard Nearest to Dark Domain may be a little hard at this point.
At Church for Two Meet, trigger the action along the center to unlock the hidden door with Philia.
After defeating the boss, you will receive the treasure. However, you receive a note from Klein to meet back at Aincrad. Do so and come back to the Hollow Area and meet up with Philia once again for some hidden door gates.