Fretton Island

You butter your toast as the mail comes. The noise shocks you in your sleep-deprived state, and you drop the knife with a clang. Cursing, you bend down to pick it up. You place it on the side before heading to your front door.
Three letters. One from the landlord, most likely an eviction notice, one from the gas company, another overdue payment, but the last one comes as a surprise.
Your name and address hand-written, quite neatly too. It's been a long time since you received a letter like this, so you eagerly rip it open.

Again, the contents were hand-written, it reads:
Dear Martin,
My name is Emily Schultz. I was lawyer to your late grandfather, George Blake. I am sorry to inform you of his demise, but I can tell you he passed peacefully surrounded by people he loved on the island he loved.
It also seems as though you are the sole heir to his estate, since your father's passing in 2009. As a result of this, George has left you an inheritance. Along with various lower-priced possessions, Mr. Blake has bequeathed unto you his holiday home on Fretton Island, his Tiritole Group Membership License and the sum of Two-million, six hundred and forty-two thousand, three-hundred and forty four dollars and twenty-six cents ($2,642,344.26).
In order to claim your bequeathment you must travel to Fretton Island and contact myself. You will find my work address overleaf.
I have included a pre-paid ticket to Fretton with this letter, your grandfathers Tiritole Membership License and instructions on how to get here.
I hope to hear from you soon.
Kind regards,
Ms. Emily Schultz,
Private Lawyer and Secretary to Mr. George Blake.

You're taken aback. You have to sit down to stop yourself from falling. Two million dollars? You haven't seen Grampa George since you were a kid. You always knew he was well-off, but you had no idea he had this kind of money.
His means nothing to you, he was your estranged grandfather that took off when you were a child. Why should you care?
You examine the letter twice more to make sure you read it right, and then you pull the ticket and a black card from the envelope. 'Seafare Ferries' was the company. It looks like you were going by boat. The card looks like an average bank card, but pitch black and no numbers. The only defining features are a pair of black shoes in the top right corner and a thick electronic strip on the back.
Still confused about the destination, you quickly check online for 'Fretton', but it only returns a couple of decent results. One is on a conspiracy theorist forum, talking about a secret government island for alien experimentation, the other shows an aerial view of an island the size of Hawaii and has the caption 'Guys, I think I found Fretton.'

You weigh up your options. This could be a joke. An elaborate prank one of your co-workers is pulling. On the other hand, you're likely to lose your house and your job within the month, and a large inheritance is perfect.

Utterly confused you have to make a decision. Stay here and get kicked out of your shitty apartment or go to this Island and receive your massive inheritance?