Hookshot

The hookshot is the item used on the little red-tipped poles you find in various places around the map.

Location

The Hookshot is a mandatory item and is part of the main questline.

Following the main questline will lead you to getting the hookshot, probably in the Thieves tower. The steps are as follows:

After you've followed the main questline until getting a quest called "Fallen Behind, Behind the Waterfall?" you'll be told to speak to a man named Garth. He's in front of a tiny square house beside a small 4x3 apple tree orchard.

Then you speak to Kalia, in the south (head to switch town, head out of the top entrance and start going left until you see a little square house in front of some trees).

She will tell you the password to get into the thieves' tower.

When at the thieves' tower, look for the cellar door among the trees below the tower.

After heading through the tower and reaching floor II (hold tab/the button to see the map and the title of the place your currently will be at the top of your screen), it'll be in the top-left-ish area, where you'll drop down a ledge and get it in a little room there.

Alternative Locations

The hookshot can also be dug up from a grave, this grave is random and won't persist between playthroughs, dig every grave to be sure!

The hookshot can also be found in the upper floors of Castle superbia, if you have been able to gain access there early.

Demo

In the DEMO, it was found in a cave in a hole under a dead tree on Hammer Island.