Final Fantasy II/Mission to Deist

Deist
Find Gordon in the main room of the building and he will direct you to take a ship at Paloom. Once you enter the town, there will be a lady standing there who offers to bring you to Deist. Take the offer no matter and you will find out that she is actually a pirate and her crew attacks you. Defeat them and she will join your party and you can control her ship to anywhere in the worldmap.

Head South East to Deist (east of snow area). Enter Deist Castle and follow the little child who will lead you to his mum. His mum will tell you that they are the remaining Dragoons clan and the only Wyvern that lives is in the room behind her but it is poisoned. She tells you to find a pendant from the Deist Caves that will allow you to speak to the Wyvern. Wander around the castle to gather all the treasures here before heading to the cave.

In the first level of the cave, head to the top right, you will find a stairs that will lead you to a carcass of a Wyvern, where you will find the pendant. Bring this pendant back to the only Wyvern. Speak to him and he will give you the last remaining Wyvern Egg. Bring this down to the bottom most level where you will find the life stream. Throw the egg into the life stream.