After our Boston detour, it's back to Amy and Dan, who are waiting for Nellie outside a rental car place.
Nellie emerges with a big brown envelope addressed to A & D Cahill from Mr. McIntyre.
They open it up, hoping it's not a bomb, and find a black light and a note telling them to meet him at Independence Hall, "but only if [they] find the information" (8.18).
Even though they're not sure what information Mr. McIntyre is talking about, they forge ahead, driving to Philly.
Nellie drops them off at the Library Company of Philadelphia, where they enlist a small army of librarians to help them with their research.
Amy scans a few documents with the black light, including Franklin's first cartoon before the librarians tell her that there are more documents at the Franklin Institute.
They get Nellie to drive them down there. Inside, they have to evade the man in black (not Tommy Lee Jones) while they search the museum, finding an armonica invented by Franklin and a request for Iron Solute. Eventually they find a hidden message on one of Ben Franklin's documents.
As they're reading the message, the Starling family sneaks up behind them and takes a picture of the cryptic clue. Those sneaky rats.
The Starlings try to make a quick getaway, but Dan tells them that it might not be safe: the man in black has been following them.
Sure enough, when the Starlings try to leave through the front door, there's a huge explosion.
Dan and Amy escape, but the Starlings are nowhere to be found.