Graveyards, good for instant horror atmosphere. Seems like a good place to hunt some ghosts.


The Set
The Box
The Instruction
The Parts
The Build


The Hidden Side theme seems to be succesful, judging by public opinion, and the fact that in January, a second wave of sets have been released. Along also came an update of the app, adding a multi-player function. JaredHinton has taken a look at the 70423-1 Paranormal intercept Bus 3000 in his review. I'll be taking a look at a smaller set, the 70420-1 Graveyard Mystery. I've picked this one, because it looked like the one that was easiest to mod to fit into a 'normal' LEGO city.

The Set

Kids can experience fun ghost-catching adventures combining an augmented reality play experience with this LEGO® Hidden Side™ 70420 Graveyard Mystery playset. This awesome app toy combines a buildable LEGO model with augmented reality for kids to deliver a fully interactive play experience. Download the Hidden Side app and scan the model with a phone to make it come alive. With continuous updates, a unique boss ghost to battle in each set, new mysteries to solve, cool items to find, games to play and ghosts to collect, this LEGO Hidden Side set gives kids a whole new way to play and interact with building bricks! Packed with cool graveyard details, this toy construction set features a dog figure, gardener figure, girl and boy minifigures, a twistable statue, grave that opens and a haunted tree with posable arms for lots of fun ghost-hunting adventures.

The Box

The box measure 35 x 19 x 6 cm, and weighs 475gr. Inside are 2 numbered bags, the instructions and a sticker sheet.

The Instructions

The instruction manuel has 112 pages with 121 steps. The pdf can be downloaded here.

The Parts

The set contains 336 parts and 12 spares, in 27 colors, and 30 part categories, with a total of 162 unique parts/color combinations. Main colors are:

Main categories are:

Most new parts have recentlty been discussed by JaredHinton in his 70423-1 Paranormal intercept Bus 3000 review. I'll only mention the parts that are not listed there already.
New part:

New prints, all found in groundskeeper:

New colors:

Rare colors:


The Build

Bag 1 builds the gate and a few graves. The angel statue can be rotated, showing different colored tiles. That will probably have some function in the app. Side-note: I didn't include the angel with the minifigs, as he/she has no legs. Underneath the lids of the graves is also a colored tile.

Bag 2 builds the groundskeeper shed. It's a fun small build with some nice details. On top of the shed is a possesed tree, that you can move using the levers in the back.



On the app part of the set, I must say I'm impressed by the technique that's used. I haven't done much with AR yet, so I have no standard against which to hold this app. But apart from that, it just looks cool. Not only is the set recognized, there is also a layer put over it, making the set come to life. For the game aspect, I think I'm not the target audience. I'm more of a Sudoku kind of gamer, so to me it looks like just a lot of tapping on anything that moves. But Fortnight is the same principle, and that game seems to have some popularity... My kids loved the game though, and seeing the app was made for their age group, that opinion counts more than mine.
One mayor issue with the app, is the device that is needed. The AR uses a special technique, that only high-end devices can handle. This meant for me, that I had to search for such a device. I only had access to a useable phone for about an hour, so I couldn't fully test the app. So before you get any Hidden Side set, with the intent to play the game: Check the compatible devices list first. Basically, if the app doesn't show in the App Store or Play Store, your device is not compatible.
I've made a video of the testing of the app:

0:00 We begin with scanning the set. Once it's found, we can start.
0:23 First target: Get the Gruwel. To do that, we need to turn the angel into the yellow tile.
0:53 Let's find him.
1:13 There he is! Now what?
1:19 Tap at the right moment to catch him.
1:30 Next color is red.
1:36 Now search the Gruwel.
1:56 There he is.
2:10 Next up is blue. We know the drill.
3:07 All Gruwels have been found. Now we need to de-gruwel a minifig. Place one on the scan plateau.
3:42 Scanning.
3:49 Ghost detected! Shoot it!
4:14 If you shoot too fast, your gun gets overheated.
4:38 Got him!
4:53 And we're done.

For the physical part of the set: It's a small but decent set. It has a good graveyard atmosphere. With a few small mods, this can easily fit within a LEGO city, so even without the app it has value to me.

Disclaimer: This LEGO set was kindly provided for review by The LEGO Group.
Anything said in this post is the opinion of the author and not The LEGO Group.
Parts- and build photographs by Tobymac (© 2020 Rebrickable)


  • 1 month, 4 weeks ago Theoderic Level 16 MOC Designer PRO
    Thanks for the review, as always, very informative.
    I am not too interested in the Hidden Side range but I read all reviews just to see whats what in the world of Lego, and I am very glad that I do. As I was reading this particular one, my long suffering wife walked past and glanced at my computer and then remarked "is that Lego?", "yes" I replied in a matter of fact manner. My wife then stated with excitement and enthusiasm "That is so cool, I have got to get that, is there any more like this?" After I recomposed myself from the shock of what I just heard, I told her that it was a new theme and there is a whole range of sets.
    So we spent the next hour or so going through the Hidden Side range and planned our next trip to the Lego Shop. It looks like the budget restrictions on Lego purchases just got thrown out of the window, so thanks TobyMac for the review that changed my life!
    • 1 month, 4 weeks ago TobyMac Level 33 Inventory Admin ADMIN
      You're welcome!
      I had a similar experience: My wife was often saying I have too much LEGO (if such a concept exists). Then she spotted the Architecture theme, and the same day she wanted to get a display cabinet.
  • 2 months ago Pioneer4x4 Level 13 MOC Designer
    I like the look of the graveyard as well.  I'm not the target for the app part either, but I think I may get this to expand on the Harry Potter graveyard set 
    since I missed out on the original graveyard duel, and it is not cheap now.
    Plus I have all the Scooby Doo sets and some Monster Fighters ones that I put out on Halloween, this will go good with that as well.
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