The magic in the Cosmos is limited by its immediate sphere of arcane or divine influence - typically within a home planet or star system. This limitation has baffled scholars and mages alike for years. Such examples include Teleportation Circle and Teleport, which have proved unable to link locations outside a star system. Scholars have fervently worked to create new spells that bypass this arcane barrier, academically termed the Bariod Limit, named for the original discoverer.
Unknown to tall, there exists a metamagical form of Teleportation Circle known as Recursion Circle, an extremely unstable and risky spell that teleports within teleports, allowing its caster to puncture the Bariod Limit. The ancient race that discovered this spell has since been lost to time - the few that pursue it hope to teleport to an unknown location for which they only know its teleportation circle sigils. Recursion Circle is an artifact-level spell whose discovery may involve entire campaigns.