It's surprisingly good at remembering earlier details. Occassionally it will forget things but another prompt tends to fix that.
For example I'm about to plan Chapter 4. The broad story so far is that the adventurers are doing some tasks for a friendly NPC and during that will slowly uncover clues to the BBEG, in this case a cabal of vampires who plan to plunge the world into darkness.
Prompting it with:
Let's plan Chapter 4. Can you produce a short table of suggested titles and themes?
It produced: Title Theme
The Vampire's Lair The adventurers infiltrate the vampire lord's castle and uncover his dark secrets.
A Deadly Dance The adventurers must navigate a treacherous ballroom filled with traps and minions.
Into the Abyss The adventurers descend into the catacombs beneath the castle and face unspeakable horrors.
The Final Showdown The adventurers confront the vampire lord and his minions in a dramatic battle for the fate of the realm.
Beneath the Moonlight The adventurers discover a hidden shrine dedicated to the vampire lord and must unravel its mysteries.
Blood Magic The adventurers face off against powerful necromancers and witches who serve the vampire lord.
The Betrayal The adventurers must confront a trusted ally who has been working with the vampire lord all along.
In table form.Now it's got a little confused, because in chapter 3 the gang already infiltrated the castle and confronted the vampire lord, but another prompt will fix that.
Prompting:
In Chapter 3, the adventurers already infiltrated the castle and dealt with the vampire lord. Can you reproduce that table assuming the vampire lord is no longer a threat for now (even if he remains at large)?
Produces: Sure, here are some possible titles and themes for Chapter 4, assuming that the vampire lord has been defeated (at least for now):
Title Theme
A Web of Deceit The adventurers uncover a plot by the cabal to take control of a powerful artifact or location.
The Hunter Hunted The adventurers are pursued by an assassin or bounty hunter hired by the cabal.
The Fallen Hero The adventurers discover that a beloved hero or figurehead is secretly working with the cabal.
An Ancient Evil The adventurers stumble upon an ancient artifact or tomb that holds the key to defeating the cabal.
The Betrayer's Gambit The adventurers are double-crossed by a trusted ally who has been secretly working with the cabal.
A Race Against Time The adventurers must complete a series of challenges or tasks before the cabal can enact their plans.
The Final Confrontation The adventurers engage in a final showdown with the cabal's leader or their most powerful agent.
(again in table form)Which are great suggestions, now I can pick one and ask it to write the next chapter based on that, at which point we can flesh out more details.