>>95828330
Scroll back to the top of the page, and check the pastebin. If you can't find what you need there, check the Share Thread, in case there is a more recent Lancer trove.

That said, you can't go wrong with the classic "You're a team of mercs hired to hunt down a pirate king" and throw your own little story together. Or if you want something more involved from the get-go, you can take inspiration from my favorite campaign.
https://imgur.com/a/lancer-rpg-arrowhead-squadron-1-12-ns95caf
https://imgur.com/a/lancer-rpg-arrowhead-squadron-13-23-MPCI7Rz
https://imgur.com/a/lancer-rpg-arrowhead-squadron-24-32-4iq2GAt