When Link arrives at Kakariko Village and meets up with Impa, it will complete the Seek Out Impa main quest objective. After talking to Impa, she realizes that Link's Sheikah Slate is incomplete and suggests that he visit Hateno Village and meet up with Purah and Symin at the Hateno Ancient Tech Lab. This will begin the Locked Mementos quest, where Link must restore the abilities of the Sheikah Slate.
Once Link arrives at the Hateno Ancient Tech Lab and meets Purah, he is tasked with restoring power to the furnace just outside the lab. Purah will task Link with bringing a Blue Flame from the Ancient Furnace in town to light the furnace just outside the lab, which will in turn power the Guidance Stone.
After bringing the flame to the furnace, the guidance stone will now be powered up, so go ahead and speak with Purah once again. She will fix the Sheikah Slate, adding the Camera, Hyrule Compendium, and Album missing files. Purah will notice that there are pictures still on the camera and since Link was Zelda's appointed knight, Link was likely present when Zelda used the camera to take those pictures. Purah suggests that Link visit Impa once again as she has a hunch that these pictures can be used to help Link restore his memory.
When revisiting Impa, Link will show her the upgraded Sheikah Slate. Impa recognizes that this is the Camera Princess Zelda used 100 years ago and will task Link in seeking out the locations of the various pictures.  This will complete the Locked Mementos main quest, while also beginning the Captured Memories Main Quest.
|1||According to Impa, the Sheikah Slate that Zelda left to guide you is incomplete.|
The director at the Hateno Ancient Tech Lab in Hateno Village may know a way to restore the Sheikah Slate's missing components.
Use the map to find the location of the Hateno Ancient Tech Lab and its director.
|2||The Hateno Ancient Tech Lab's director can't fix the Sheikah Slate until the Guidance Stone is operational again. The only way to power the Guidance Stone is to light the furnace on the outer wall of the tech lab with a blue flame.|
Carry the blue flame from the ancient furnace in Hateno Village to the tech lab, and use it to light the lab's furnace.
|3||The blue flame in the furnace is now powering the Hateno Ancient Tech Lab's Guidance Stone.|
Report to the director so that she can repair your Sheikah Slate.
|4||Purah has fixed the Sheikah Slate, restoring the last of its basic runes from 100 years ago.|
Snap an image of Purah using the Camera rune!
|5||You proved the Camera works again by capturing an image of Purah!|
According to Purah, the album already has pictures from the past in it.
Where could these have come from? Impa in Kakariko Village may have the answer.
|Complete||You let Impa know that the basic runes of the Sheikah Slate have been restored.|
She told you that the pictures in the album are Zelda's memories from 100 years ago.
Visit the various spots shown in the images Zelda left behind to recall your own memories from that era!
- ↑ ...It seems to me that your Sheikah Slate is not yet complete. The device Princess Zelda left you is your guide and also your memory. Now, let's see... Someone at the research lab in Hateno Village might be able to help you... - Impa, Breath of the Wild.
- ↑ The location shining on the eastern edge is Hateno Village. It is a small village... One of the very few places that avoided suffering significant damage during the Great Calamity. - Impa, Breath of the Wild.
- ↑ You are Princess Zelda's only hope... and Hyrule's, as well... You cannot turn back now. Follow your heart and seize your destiny! - Impa, Breath of the Wild.
- ↑ All right, then. First I need you to run an errand for me. ... What's with that look on your face? You didn't think I'd fix your Sheikah Slate for free, did you? Hmmm... Post Slumber of Restoration, subject is plagued by...presumptuous... tendencies. Noted! Let me explain what this errand entails. You know the unlit furnace on the wall just outside this laboratory? Could you please bring the blue flame from the ancient furnace in town? Oh, and also use it to light our furnace? This sweet little Guidance Stone will start working once you do that, allowing us to restore your missing runes! - Purah
- ↑ Huh... I wonder if young women these days still say things like "sweet" and "little." Ah, well. I suppose it doesn't matter anyway. - Purah
- ↑ OK then. I'm counting on you for that blue flame! - Purah
- ↑ Camera, Hyrule Compendium, and album missing files confirmed. Starting repair. - Guidance Stone
- ↑ Yes, there are also some old landscape photos stored in the album. I know Princess Zelda had made frequent use of the Camera feature, but this... Hey, Linky! It dawns on me that you were Princess Zelda's appointed knight, which means... there's a strong possibility that you accompanied her to all of the places where these pictures were taken. - Purah
- ↑ Oh...right. The "lost memory" thing could prove troublesome. But don't lose hope! It just means these pictures could be the missing piece to help restore your lost memories! If my hunch is correct, I suggest you check in with Impa. She knows more about Princess Zelda than even I do! ... Oh, yeah! There's just one more thing I need from you! You don't have to worry about this until after you see Impa, but I want you to bring me back some ancient materials! Bring them either to me or to Robbie at the Akkala Ancient Tech Lab. As if my joy weren't enough, if you bring us ancient materials, we'll give you something good as a reward. All right! Let's do this! - Purah
- ↑ Now then... Let me see. Aha! This is, without a doubt, the Camera that Princess Zelda used 100 years ago. - Impa, Breath of the Wild.
- ↑ It could be that if you visit the locations within those pictures, you will be able to restore some of your lost memories. Come back here once you have tried going to at least one of those locations. There is something I wish to give to you. - Impa, Breath of the Wild.