As Philippa told you, she will need to utilize an “ungodly” amount of magic power to restore Saskia to her former self. It will be up to you to find the source of this power and deliver it to her, as she cannot seek it out herself as long as Saskia’s life rests in her hands. Talk to Philippa after obtaining this quest to get a lead or two on where you might be able to obtain a magical crystal containing the necessary power. She in turn will implore that you speak to the townspeople for further clues. Three civilians in particular are noteworthy here.
The first is Skalen. You can usually find him in his home, located on the ridge across from the tavern. If not here, search inside of the tavern. He will tell of a powerful sorcerer who used to live in the forest that borders the city and suggest that you search the outskirts of the area, specifically in the old ruins that dot the landscape. Talk to the innkeeper next, who will suggest that you seek out an NPC named Cecil.
Head towards the northern side of town and take the tunnel on the right. Then go up through the tunnel to the left before hanging another right. Walk through this final tunnel and up the ridge to reach Cecil. He will tell you of a specific tower on the outskirts of the town which may be of interest to you. The nearby road should lead you right there. Jump over the obstacles blocking your path and follow it to its end. When you have the tower in sight, draw your Silver Sword, as a group of Harpies is about to swoop down and attack you. Beware the leader of the group, the Celaeno Harpy. This creature will stand out from the others due to her intimidating size and brightly glowing claws.
Dodging is an important tactic when it comes to felling a
Harpy, as their wings allow them to attack from many angles. Your magic may
also not be of much use here, as Aard is rarely quick enough to catch a Harpy.
Just focus on using your sword instead, and kill off the smaller enemies before
moving on to the Celaeno Harpy. Approach her the same way you might a typical
Harpy, but beware of her stronger attacks and larger health bar.
Once the Harpies are dead, success is a simple matter of heading to the tower, looting the crystal, and returning it to Philippa. Unfortunately, it will turn out that the crystal you have obtained is not strong enough to fuel the sorceress’ magic. She will, however, shed some interesting light on the Celaeno Harpy you just killed. These Harpies are often called Dream Snatchers due to their ability to suck the dreams from humans and bind them into crystal form. If you can find a crystal that contains a strong enough dream, you may be able to power Philippa’s magic and save Saskia yet. She will also inform you that the crystal that you snagged from the tower contains Cecil’s dreams. Head back to Cecil to get the key to the Harpy’s Lair, which is located to the south of the city. You will also unlock the quest The Queen Harpy Contract.
Before you can complete Hunting Magic or the Queen Harpy Contract, however, you’ll need to accept a few more missions and stock up on items. For now, simply focus on finding the rest of the items on Philippa’s list. Upon gathering those and completing a few other quests, you will return to finish Hunting Magic.