To start, talk to Redbeard Frank in Port Sarim pub.
Redbeard Frank: Arrrh matey
Player: I'm in search of treasure
Redbeard Frank: Arrrh treasure you be after eh?
Redbeard Frank: Well i might be able to tell you where to find some.
Redbeard Frank: For a price
Player: What sort of price?
Redbeard Frank: Well for example if you can get me a bottle of rum
Redbeard Frank: Not just any rum mind
Redbeard Frank: I'd like some rum brewed on karamja island
Redbeard Frank: There's no rum like karamja rum
Walk along the plank to Seaman Lorris and go to karamja for 30gp. The ship will arrive at karamja. Go west to a shop and talk to Zambo. Buy a karamja rum for 30gp. Don't go back to the ship otherwise the customs officer will confiscate your karamja rum. Go east and talk to Luthas. Ask him if you can be offered an employment on his plantation. Go to the banana trees and pick lots of bananas until your inventory is full. There are 5 bananas to a tree. Go to the crate outside Luthas' house and use banana with crate. Ten bananas fill a crate. Use all the bananas with the crate until it says that the crate is already full. Now use the karamja rum with the crate and talk to Luthas again and ask for your payment. Talk to the Customs Officer and ask to go back to Port Sarim. There will be a shop in Port Sarim that is owned by Wydin. Click open door and he will say you can't go in there. Ask for a job there. You will need to be wearing a white apron which you can buy in Varrock clothes store. Search the crate round the back and you will get your karamja rum. Go back to Port Sarim pub and talk to Redbeard Frank.
Redbeard Frank: Arrrh matey
Redbeard Frank: Have ye brought some rum for yer old mate frank
Player: Yes i've got some
Frank happily takes the rum
Redbeard Frank: Now a deals a deal, i'll tell ye about the treasure
Redbeard Frank: I used to serve under a pirate captain called one eyed hector
Redbeard Frank: Hector was a very successful pirate and became very rich
Redbeard Frank: But about a year ago we were boarded by the royal asgarnian navy
Redbeard Frank: Hector was killed along with many of the crew
Redbeard Frank: I was one of the few to escape
Redbeard Frank: And i escaped with this
Frank hands you a key
Redbeard Frank: This is hector's key
Redbeard Frank: I believe it opens his chest
Redbeard Frank: In his old room in the blue moon inn in varrock
Redbeard Frank: With any luck his treasure will be in there
Player: Ok thanks, i'll go and get it
Go to the blue moon inn in Varrock and go up the ladder. There should be a chest which you use the key with. There is a message which says dig behind the south bench in the park. The park is in Falador and you will need a spade. Go to falador with a spade (spades can be found at the exit of draynor manor) and go to the park which is where Wyson the gardener is (he sells woad leaves). There should be 2 flowers behind a bench (south), use your spade with the flower, he will say: Hey leave off my flowers and he will come and attack you. You will need to kill him otherwise you won't be able to do the quest. When you have killed him, use the spade with the flower and you will recieve 450gp, a gold ring, and a cut emerald. You will also gain 2 quest points.