What to know
- Fireworks are a single collectible item, not a craftable tool
- They are required to unlock the Light Up the Sky trophy/achievement
- You must use them at a Short Break rest point, nowhere else
- The item is hidden near the Kami Cable Car route, off the main path
In Cairn, fireworks are not a flashy traversal gadget or a puzzle mechanic. Instead, they exist purely as an optional interaction tied to an achievement. Because of how tucked away they are—and because the game never tells you how to use them—many players finish Cairn without ever seeing them. This guide walks through exactly where to find the fireworks, how they work, and how to trigger the Light Up the Sky trophy without wasting time backtracking.
Cairn fireworks quick overview
| Element | Details |
|---|---|
| Item type | Collectible keepsake |
| Purpose | Unlocks Light Up the Sky trophy |
| Where found | Near Kami Cable Car path, hidden cave |
| Inventory required | Yes |
| Where usable | Short Break rest points only |
| Story impact | None |
What the Light Up the Sky trophy is
Light Up the Sky is a missable optional trophy/achievement in Cairn. It unlocks the moment you successfully launch fireworks from a valid Short Break rest point. The fireworks do not affect weather, stamina, climbing routes, or progression. Their only function is to trigger this achievement, making them easy to overlook unless you know exactly what to do.
Because Short Breaks appear throughout the mountain, the challenge is not finding a place to use the fireworks—it’s knowing where to find them in the first place.
Location of Fireworks in Cairn
The fireworks are obtained during the Kami Cable Car section of the climb. As you move through this area, look beneath the cable car structure rather than along the main ascent line.
Your first clue is a trash can underneath the cable car, which contains a map. This map is easy to miss if you stay focused on vertical progress, but it’s the key to locating the fireworks. Picking it up reveals a side route that leads away from the standard climbing path.
Following the map’s direction takes you toward a hidden cave branching off from the route commonly associated with The Shortcut or The Terraces portion of the mountain. This cave is not visible from above and requires intentional detouring to reach.
Inside the cave, you’ll find the fireworks item lying on the ground, surrounded by minor loot. Once picked up, the fireworks are stored in your inventory like any other keepsake. There is no prompt explaining how they work at this stage.
How to use fireworks at a Short Break to get Light Up the Sky trophy
Using the fireworks is more restrictive than picking them up. You cannot activate them while climbing, standing still, or at the summit.
Step 1
Carry the fireworks in your inventory and travel to any Short Break rest point. These are the small cairn-marked spots where your climber sits down to recover.
Step 2
Interact with the Short Break and rest normally. The fireworks must already be in your inventory before you sit.
Step 3
While resting, a new interaction option appears allowing you to launch the fireworks. Select it.
Step 4
The fireworks fire into the sky, and the Light Up the Sky trophy/achievement unlocks immediately.
If you rest at a Short Break without the fireworks in your inventory, the option will not appear.
Where fireworks do and do not work
Fireworks only function at Short Breaks. Attempting to use them at the summit, on ledges, during storms, or mid-climb will do nothing. This restriction is what causes most confusion, as the item description does not explicitly explain the requirement.
Once used, the fireworks are consumed and cannot be reused, though this has no downside since the trophy unlocks instantly.
Why players miss the fireworks
The fireworks are hidden in a way that goes against Cairn’s usual visual language. The trash can under the cable car looks like background detail rather than an interactable object, and the cave route is easy to skip if you’re focused on elevation rather than exploration.
Additionally, the game never hints that fireworks exist, nor does it suggest that resting can trigger unique interactions beyond stamina recovery. Unless you experiment at a Short Break after picking them up, the achievement can remain locked indefinitely.
Practical tips before going for the trophy
If you’re already near the Kami Cable Car area, grab the fireworks as soon as you find the map to avoid forgetting later. You don’t need a specific Short Break—any one will work, so feel free to trigger the trophy at the next safe rest point you reach.
Because the item has no gameplay value beyond the achievement, there’s no benefit to holding onto it for later sections of the climb.
