It didn't take long for the Resistance to confirm there was First Order activity on Aquilaris. While the First Order's objective for occupying the planet remained unknown, scouts were able to obtain holograms of machinery on the surface that appeared to be used for mining purposes.
"That doesn't make sense," one fighter pilot commented. "Aquilaris is primarily covered in water,"
"The key word is primarily," Poe reminded the pilot. "There are rocky formations on the surface, not to mention underwater caverns as well,"
The difficult part was getting Resistance members on the islands or into buildings that jutted out of the water. First Order checkpoints were everywhere, and the Resistance didn't have the resources to equip everyone with falsified credentials. Even if they had the means to do so, very few in the galaxy were vacationing on Aquilaris this soon after the fall of Palpatine and rise of Vader (those who were had been spending their credits at Canto Bight). With this in mind, the Resistance was only able to send in a couple people, aliens, and droids to gather intel.
When it comes to war, sometimes even the most thorough strategies can only work for so long. It was during one of these intelligence-gathering missions that one of the Republic spies was followed back by a member of the First Order. Upon the realization that one of the "vacationers" was indeed with the Rebellion, word traveled immediately to the First Order, wherein they instantaneously reacted.
"They're coming after us!" the Resistance spy managed to shout into his comm before it crackled and fell silent. As the contact severed Rey broke away from the other leaders who were listening and went straight to the armory. As soon as Rey was geared in her washed grey armor and had her orange lightsaber attached to her side, she made her way to her assigned X-wing with R2-D2 in tow.
The time had come.