Permanent and non-repeatable game mode in NIKKE where you can unlock Harmony Cubes and get rewards as you clear every Lost Sector. It’s unlocked after clearing 5-3 in the main campaign, and you can see the requisites for every Lost Sector in the main screen.
![](https://lootandwaifus.com/wp-content/uploads/2023/03/lost-sector-levels-1024x538.webp)
You can also preview all the rewards for the next available Lost Sector and the completion reward if you clear 100% of it. We recommend clearing every level as you unlock them, Harmony Cubes are an important part of the builds of your characters.