Exposition, the fiction-writing mode for delivering information, may be delivered by three methods:

• Narrative exposition (where the all-knowing, impersonal, and invisible narrator simply states it)
• Expository devices (treasure maps, diaries, newspaper clippings, etc.)
• Characters (by what they say, hear, see, smell, feel, think, or recall)

Each of these techniques has advantages and disadvantages, and each requires skillful presentation for effective use.

One of the most effective ways to present information through a character is during the thinking phase of a sequel. The character is already in thought as he reviews recent events, analyzes the situation, considers his options, and begins to develop a plan.  

Information may surface in a sequel through various channels. The character may simply recall information from the recesses of his mind. Information may be revealed through a flashback scene, where the character relives a significant moment of his past. Other characters may provide information through dialogue if that part of the sequel is portrayed verbally.  

We tend to remember information best when it is steeped in emotion (Can you remember your first kiss?), and since a sequel begins with emotion, it is a particularly effective place to convey information.  

The right time to present information is when the reader most needs it, and what better time to share information than when the character is reviewing events, analyzing his situation, or considering his options--as in a sequel?

The amount of exposition that can be effectively presented in sequels is limited only by the needs of the story and the imagination of the author. Think of the massive amount of information revealed by Dan Brown in his hugely successful novel The Da Vinci Code.