Clavia asks you to find out what Reede is up to.
Quest Location
Talk to Clavia in Hateno Village to start the quest. She can be found in Zelda's house (south of the East Wind General Goods store) during the day.
How to Complete the Quest
Sit by a fire until noon or rest at the inn until noon. Then go down the Hateno Village West Well and go southeast (through the tunnel on the right) until you see a wall of boulders and a wall of vines. Look at your map and you will see that you are directly beneath the quest location (make sure that you have selected this quest in the Adventure Log, to display the quest location). Use Ascend to enter the shed, then read the diary.
Then you can use the door to leave the shed. Go to the quest location to find Clavia. Talk to her to tell her what you found out.
Quest Reward
Clavia gives you 10 Hylian Tomatoes.