Few days before the impending time of their war, of course no one knew exactly when Leo and the others would return, but Kaoru could feel how the barrier have been weakening. Eureka had been training on her own all this time.
The others tried to pull her into going around with them, but the one who initiated this kind of things rejected them entirely. They could only scratch their head, wasn't it you who told us to just enjoy, you even pulled Raven along. So why is it now that you are the one training rigorously? Are you making us feel guilty?
Thinking back, she suddenly returned to her training right after a talk with sir Dai. This happened before she and her family had their little moment by the lake. They tried to ask her what they talked about, she said she just gave him a plan. But that plan, she herself has no plan on disclosing to them.