Is LEGO Hidden Side worth collecting now? Yes, for the right buyer. The theme ran from August 2019 to December 2020, only 32 sets total, and the companion AR app was shut down for good on January 1, 2023. That combination of a short production run and a dead digital hook has pushed some figures and sets higher on the secondary market, while others still sit flat. In my experience sorting through bulk lots, Hidden Side is one of those "sleeper" themes that a lot of casual sellers walk right past.
I started paying closer attention to Hidden Side after noticing how often the ghost themed minifigures showed up underpriced in Facebook Marketplace lots and garage sale boxes. Most sellers remember Star Wars and Harry Potter figures on sight, but Hidden Side characters like the Shadow-Walker or Nehmaar Reem just read as "random monster guy" to someone clearing out a closet. That gap between perceived value and actual value is exactly where resellers make money.
- LEGO Hidden Side launched in August 2019 and was discontinued by December 2020, a run of roughly 16 months.
- The Hidden Side AR app, which powered the ghost hunting gameplay, was officially shut down on January 1, 2023.
- Set 70437 Mystery Castle released in June 2020 with 1,035 pieces and a $99.99 MSRP, then retired that same December.
- Several exclusive Hidden Side minifigures, including variants of the Shadow-Walker and Nehmaar Reem, carry some of the highest used and new prices in the theme.
- Scan your own Hidden Side figures with brick'em's minifigure database before you price a lot, since values shift and guesswork costs money.
What Is LEGO Hidden Side and Why Was It Discontinued?
LEGO Hidden Side was a ghost hunting theme that paired physical sets with an augmented reality app, letting kids scan their builds to reveal hidden monsters and animations. It launched in August 2019 and was pulled from the lineup by December 2020, a run of about 16 months and 32 total sets. LEGO retired it faster than most multi year themes, likely because the AR gimmick didn't hold attention the way minifigure driven themes like Ninjago or Star Wars do.
The app itself limped along for a while after the physical sets stopped shipping, then LEGO officially discontinued it on January 1, 2023. That shutdown mattered more than most app retirements because the gameplay was the point. Without the app, a Hidden Side set is just a nicely designed haunted house or truck model. I noticed this shift firsthand when I started seeing more complete, unopened Hidden Side boxes show up in bulk lots from parents who bought the sets for the app experience and have no reason to keep them once that experience disappeared.
Is LEGO Hidden Side Worth Collecting in 2026?
Hidden Side is worth collecting selectively, not as a blanket rule. It's a short, fully retired theme with a handful of genuinely scarce minifigures, which checks the boxes collectors look for: limited supply and no chance of a restock. But most of the common human characters, like Chuck or Bill, were never scarce and probably never will command much. In my view the real opportunity in Hidden Side is narrow: a few exclusive monster figures and a couple of boxed sets, not the full catalog.
From what I've seen trading in this space, themes that combine a short production window with a clear "why it ended" story tend to hold collector interest longer than themes that just quietly faded out. Hidden Side has that story built in, which is part of why it keeps showing up in retired theme searches even years later.
Which Hidden Side Minifigures Hold the Most Value?
The most valuable Hidden Side minifigures are the exclusive monster and ghost characters, not the human cast. Figures like Nehmaar Reem, the Shadow-Walker variants, and Terry Top consistently price higher than the detective and teen characters because they were harder to pull and tied to specific, lower production sets. Here's a snapshot of current catalog pricing from brick'em for some of the stronger performers in the theme.
| Minifigure | Used price | New price |
|---|---|---|
| Nehmaar Reem (hs066) | $16.29 | $26.85 |
| Shadow-Walker, Wings (hs069) | $12.19 | $18.33 |
| Shadow-Walker (hs065) | $9.87 | $14.86 |
| Nehmaar Reem, The Harbinger (hs073) | $9.65 | $47.65 |
| Shadow-Walker, Hood (hs071) | $8.73 | $11.01 |
| Terry Top (hs039) | $7.03 | $9.71 |
| Claus Stormward (hs054) | $5.68 | $8.70 |
Those numbers will drift over time since this is a resale market, not a fixed price list, so always check current sold listings before you quote a price to a buyer or seller. I personally keep a short list of the top five or six figures in any retired theme memorized, and Hidden Side's list is short enough that it's an easy one to learn.
What Is Set 70437 Mystery Castle Worth Today?
Set 70437, Mystery Castle, is one of the last and largest Hidden Side sets, and it's a reasonable target if you want one set that represents the theme. It released in June 2020 with 1,035 pieces at a $99.99 MSRP, then retired that same December, giving it one of the shortest retail windows in the whole lineup. It included several minifigures, with reports differing on whether it's five or six, and at least two of those figures were exclusive to this set.
Because it's a bigger, boxed set rather than a small vehicle set, condition and completeness matter a lot for Mystery Castle specifically. A complete, built set with all the figures is worth meaningfully more than a part out, and a sealed box is its own separate market from either. I recommend checking current sold prices on BrickLink and eBay rather than trusting any single number you read, since a 1,000 plus piece retired set like this one moves in price as supply tightens.
How Does the Missing App Affect Resale Value?
The app shutdown mostly strips away play value, not collector value, and that split is worth understanding before you price anything. A kid who buys a used Hidden Side set today can still build the model, but can't trigger the ghost hunting AR features that made the theme unique, since the app has been gone since January 1, 2023. That makes Hidden Side sets less appealing to parents buying for active play and more appealing to collectors buying for the build and the figures.
In my experience that shift actually helps serious sellers. Casual buyers who don't realize the app is gone sometimes skip Hidden Side listings entirely, which thins out demand from people who'd complain about a nonfunctional app, and leaves the field to buyers who want the set for what it physically is. When I sort incoming bulk lots, I treat any Hidden Side box as "build and figure value only" and price it accordingly.
Where Should You Buy and Sell Hidden Side LEGO?
BrickLink is the best fit for individual Hidden Side minifigures and loose parts, since it's the closest thing the hobby has to a standardized price reference, sometimes called the Wall Street of LEGO. eBay reaches the widest pool of casual buyers and tends to move complete sets fast if you price 30 to 50 percent under recent sold comps. Whatnot works well for building a following around retired and niche themes like this one if you can commit to a regular show schedule, and Facebook Marketplace is still the best place to source cheap, unidentified Hidden Side lots from people clearing out a kid's old bin.
A seller I know built a decent chunk of their early inventory just by searching "ghost lego" and "haunted lego set" on Facebook Marketplace, since a lot of parents don't know the theme's actual name. That's a cheap, repeatable way to find Hidden Side stock before other resellers start specifically searching for it by name.
Checklist: Evaluating a Hidden Side Lot Before You Buy
- Check whether minifigures are the exclusive monster variants (Shadow-Walker, Nehmaar Reem, Terry Top) or common human characters.
- Confirm the set number and cross reference it against a current pricing source before making an offer.
- Inspect completeness. Missing pieces matter more on larger sets like 70437 Mystery Castle than on small vehicle sets.
- Separate "sealed box" value from "built set" value. They are different markets with different buyers.
- Remember the AR app is gone, so don't pay a premium for "working app features" that no longer exist.
- Run the figures through brick'em's minifigure database to confirm current used and new pricing before you commit to a purchase.
Is LEGO Hidden Side a Good Long Term Investment?
Hidden Side can be a reasonable long term hold for a handful of exclusive figures and a couple of boxed sets, but it isn't a guaranteed appreciation play across the whole theme. Retired, short run themes do tend to get scarcer over time, and Hidden Side checks that box, but demand still depends on nostalgia and character appeal, and ghost hunting kids from 2019 are a smaller fan base than, say, Star Wars or Marvel buyers. I'd treat this as a selective pickup, not a core holding.
Heads up: This is not financial or legal advice. We're sharing what we've learned from the LEGO reselling community.
If you're trying to decide whether a Hidden Side lot is worth the money, run the numbers before you buy rather than after. brick'em's haul calculator can help you total up what a mixed lot is actually worth at current prices, and the collection value calculator is useful if you already own a stack of Hidden Side sets and want a current snapshot instead of guessing.
Frequently Asked Questions
Is LEGO Hidden Side still available at retail?
No, LEGO Hidden Side was fully discontinued by December 2020 after a roughly 16 month run of 32 sets. A small number of individual pieces, like the stunt cannon vehicle, have occasionally reappeared in some regions, but the theme as a whole is retired and won't be restocked by LEGO.
Why did LEGO discontinue the Hidden Side app?
LEGO shut the Hidden Side companion app down on January 1, 2023, ending the multiplayer and AR ghost hunting features that the sets were built around. The exact internal reasoning wasn't published in detail, but the app had already seen limited updates for a couple of years before the shutdown, which usually signals winding down support.
What are the most valuable LEGO Hidden Side minifigures?
The exclusive monster and ghost characters hold the most value, including Nehmaar Reem, the various Shadow-Walker variants, and Terry Top. These price well above the common human detective and teen characters because they were tied to fewer sets and had a narrower window of availability before the theme was retired.
Where is the best place to sell LEGO Hidden Side sets?
BrickLink works best for individual minifigures and parts, eBay is strongest for moving complete sets quickly to a broad audience, and Whatnot can work well if you're building a following around retired themes. Facebook Marketplace is better for sourcing cheap, unidentified lots than for selling at full value.
Should I buy LEGO Hidden Side as an investment?
It can make sense as a small, selective investment in a few exclusive figures and larger boxed sets, but it isn't a sure thing across the entire theme. A lot of sellers I know treat retired, short run themes like this as a speculative slice of a collection rather than its foundation, and that's a reasonable way to think about Hidden Side too.
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