Chapter 8 and its main mission A Precious Source of Power is a very short one compared to what you've seen previously, but you could argue is a welcome spot of respite following the dungeon and its two bosses of Chapter 7.
A Precious Source of Power
Recommended level: 27
Head up the gangway and turn left to meet with your new partner. Follow him inside and deal with the handful of Goblins and Garchimaceras (vulnerable to Swords, Shields, and Fire, and resistant to Lightning) around the inner walkway.
After the first batch you'll be given a five minute timer to defeat the rest, but there aren't many so the time limit isn't too taxing - just work your way round in a circle until they're defeated, then leave the way you came in.
Need more help? Our Final Fantasy 15 guide and walkthrough can provide tips on main story, as well as the open-world's many quests and activities. Learning how to get AP fast, EXP fast and money or Gil fast will aid you in many optional dungeons and tombs - including how to open and explore their locked doors. There's also plenty of interesting side-quests, too, such as the Scraps of Mystery and Professors Protege frog locations. And if you want to get around easier, you can rent a Chocobo, learn the infinite sprint trick and later in the game, get the flying car Regalia Type F. There's also more to see and do with DLC, such as Episode Gladiolus and Episode Prompto.
Brave New World
Recommended level: 29
You're back in Lestallum and reunited with the whole party now, so head for the Regalia and drive back to Cape Caem.
Getting on the lift in the lighthouse will lock you away from the open world for a bit, so make sure you finish up anything you were doing first. (A lot of new side-quests across the world have been opened up, and while you can always do them later, it could be a good time to do a few now to raise a few levels).
Whenever you're ready, talk to Iris and Cor near the dock, to begin Chapter 9 as you then set sail for Altissia.