You have to beat Big Nate on the ski boats and get the map that is under the rocks. :)
you have to beat Nate on the jet
you leave and and race nate for the map
follow it
Big Nate Island on the Poptropica map is the 9th from the top.
Go to your blimp and travel across the map to Big Nate Island.
where the chatty girls are.
go to puffin point and go on the speed boat and race big nate. when you win go on top of the rock where the 2 seals are and push them to the left side then click on the map and you will have the map:)
if you don't get the keys you can't beat nate to get the map for the school.
When you get the dog to dig the hole where it shows the X on the map you find not the Big Nate map the map you have to find and then take the box out but it wont take the whole thing out just the the half the box then click on the golden square which is the keyhole then you get it!
Tilt the rock by moving the seals to the left side. You can now retrieve the paper, which is a map to the Time Capsule on Big Nate island.
You go to the harbour and click on the jet skies. after that you will compete with Nate to the island with the map.