- Head to the Temple of Zeus in Sami.
- Talk with the Priestess and she will tell the Descendant about the Spear of Kephalos.
- Summon Ikaros and have them travel to the North.
- Look for the nearby pit in the hillside.
- You will find the mentioned Melissani Cave just to the North.
- Go to the Cave and dive in.
- Turn to the West and climb up into the tunnel entrance there.
- Dive into the water there and swim through the water-filled cave.
- This will lead to a new section of cave.
- Go along the tunnel to the West and then South.
- This will lead to a small Bandit camp found hidden inside.
- There are 2 Bandits found here, guarding a chest.
- Keep in the nearby bushes and use the Whistle to lure in the Bandits one at a time.
- Defeat them and then open the nearby chest.
- This will give you the Spear of Kephalos.