The Great Plan functioned as a sanctuary for those seeking refuge; it was situated within the Caverns of Forever, an interconnected network of caverns located on the planet Cularin. Access to these caverns was gained from beneath the ch'hala Heart Tree. The roots of the ch'hala tree enveloped both the caverns and the refuge, permeating them with the vital energy of all ch'hala trees growing on Cularin. This energy, channeled through the Force, served to conceal anyone present within the shelter. Mother Dariana, the leader of the Tarasin Hiironi irstat, secretly maintained the Great Plan, intending it as a haven for the Tarasin people. She only considered revealing its existence to them as a last resort, prioritizing their safety. However, as the Clone Wars raged, Dariana and her associate, Jedi Master Lanius Qel-Bertuk, foresaw an impending darkness engulfing the galaxy. Consequently, they decided to open the refuge to the Jedi from the Almas Academy and anyone else seeking protection from malevolent forces and the influence of the dark side of the Force.
Around 19 BBY, Qel-Bertuk sacrificed his life to safeguard the Heart Tree from corruption by the dark side of the Force at the hands of the [Wyrd], a group of Tarasin witches. Following his passing, Dariana guided the Heroes of Cularin, a band of independent agents who had aided Qel-Bertuk in his struggle, into the Great Plan. Her purpose was to demonstrate the importance of protecting the Heart Tree and to offer them sanctuary within the refuge should they ever require a place to hide.