Five months ago, a team of senshi were sent to a remote planet to answer a cry for help that had been addressed to the senshi of the Solar System. Once there, they found themselves trapped in a metallic maze, pitted against robotic creatures to save a young woman they were never completely sure was on their side. The trial left them drained and unsure, but they survived it nonetheless, with one of their captors dead - killed by the mastermind of the trap - and the other left supposedly stranded on the planet. The girl they went to save planted herself with them, and gave them information about the man in charge. 
She described him as devilishly handsome, and incredibly intelligent.

As they escaped that cursed planet, Sailor Achelois felt a disturbance within her heart - someone, or something, was attacking her homeworld. She left immediately to face the threat, and the rest of the team split - roughly half following her to help if they could, while the other half headed back for the Solar System. 
On planet Achelois, Sailor Achelois was able to find and defeat the threat with relative ease based on her role as the planet's goddess and the immense wealth of power she had while connected to her star; the culprit had been a seed. This seed had sprouted its roots in her planet, blackening anything it came in contact with. While Achelois was able to reverse the process, she was startled with how quickly it had grown. 

The teams met up again just outside the Solar System, which was now encased in a shell of garnet-colored energy - a force-field had been erected to keep everyone out of the Solar System. Finding entrance on the dwarf-planet Pluto, the team met Guardian Pluto, and from her learned that all of the Solar Systems defenses had been enacted - protections from Pluto, Neptune, and Uranus were in place to guard against any and all outsiders. No one was allowed to enter the Solar System. Through communications between the Pluto Castle and Earth, they were able to connect with Sailor Jupiter whom, along with King Endymion and Neo Queen Serenity, were alone with the people of Earth, the other senshi being out in the galaxy to fight against the rise in Chaos. From Jupiter they learned they had been presumed dead, for what was only days to them had been five months in real time. During those five months, Chaos had risen, his agents attacking planets all throughout the galaxy. Their leader had yet to emerge, but they alone were enough trouble. Senshi had gathered to fight off this threat, and as soon as one case was quelled, several more popped up in their stead.
They were overextended. They needed help. Many of the team were going to volunteer to help where they could, when all of the sudden two of their own announced that their planets were under attack, chaos spreading in the same way it had on Achelois. Ribbon, the girl they saved from the planet, revealed that their planets could be attacked out of revenge for foiling her ex-master's plot - the maze planet they had been stuck in had been meant for the Solar System Senshi, and had those senshi appeared this galaxy-wide takeover would have happened quickly and quietly. He saw it as their fault his plans did not go so smoothly.

Suddenly, both Sailor Leviathan and Sailor Andromeda felt Chaos's presence on their planets, and announced it to the rest of the group. As they discussed what course of action they would take - which planet to clear first before heading to the other, Leviathan, unable to wait, took off for her planet and her people; Shadow followed after. The rest of them decided to clear Andromeda first, and then take the battle to planet Leviathan. As they prepared to leave for Andromeda, Sailor Enyalius, too, felt the disturbance, but did not mention it. 

Upon arriving on Andomeda, the group came to the scene of an angry mob attacking the Royal Palace; shortly thereafter they reunited with Sailor Andromeda, who had been trying to calm the people and protect her family, and then time stopped. The group was met by an old woman who appeared from nowhere and gave them gifts, though treated the exchange as a delivery of paid-for goods. She was criptic and judgemental in the way that crotchety tired old ladies could be, and with a warning and some hints about the true nature of the situation, she left. 

The team made for a newly formed structure in the middle of a hurricane that was engulfing the small planet Andromeda; once there, they worked together (mostly?) to combat the threat within and, with Andromeda's power magnified by her planet, were able to destroy the chaos seed that was taking hold within the Andromeda Spire. 

Their task complete, they turn to Leviathan.