Another node is added to the right of the Void Beyond node in the Historia Crux - that one being the Coliseum (you've already done everything you can in the Coliseum, so don't visit). Pick the Void Beyond node instead and off you go.
Throne of the Goddess - After the scenes loot a treasure sphere for 6x Potent Chip . Along the south edge of this area are two treasure cubes out of reach. Toss the moogle at them to pocket the 'Prediction' Gate Seal (unlocks Time Reversal in AF??? Coliseum) and 'The Calm' Gate Seal (unlocks Time Reversal in AF??? Archylte Steppe). And lastly, there's a concealed treasure sphere in the northeast corner of the area. Uncover it with Moogle Hunt and cash in 800 gil. Now exit the Void Beyond to unlock AF400 Academia and AF??? Serendipity. Let's visit the latter!