First, we see a few pages from Grandfather's notebook, which are things that he wrote to Oskar in the last chapter: "I don't speak, I'm sorry." "My name is Thomas." "I'm still sorry."
He writes to the younger Thomas about how he's about to go with Oskar to dig up his empty coffin.
But first, some backstory.
Grandpa writes about giving a note to Grandma's doorman on 9/11/01 and how it took a while for her to agree to see him again.
After a few days, she lets him into their guest room (a Nothing space, if you remember).
Let's flash back again, to Grandpa getting off the plane.
The customs agents ask him questions, but he can't verbally answer them.
They also wonder why he's lugging around a suitcase full of papers.
He explains that they're letters to his dead son, which he couldn't deliver.
As soon as he gets out of the airport, he calls Grandma.
Since he can't speak, he tries to communicate with her by pushing the buttons on the phone.
He writes out about 4,000 numbers, but we don't speak that language (and neither does anyone else!).
A few days later, the World Trade Center was attacked.
Grandpa writes that on that day he lost everything for the second time.
Grandpa reads the newspaper and finds an obituary for the son he never got to meet. (Tissues, please.)
It's that day Grandpa goes to Grandma's apartment with a piece of paper that says "I'm sorry" and she lets him back into her life.
Eventually, Grandma and Grandpa get naked and touch each other (like an X-rated version of Best Exotic Marigold Hotel).
Later, Grandpa asks if he can see Oskar, but Grandma says no.
He watches Oskar anyway, through the keyhole in his bedroom door.
One day, Grandma tells Grandpa about Thomas, "Not our son, my son" (14.1), she emphasizes.
She tells him that she gave him the one letter he ever sent (this must have been the one marked with red pen) when he wanted to find his own father.
Grandpa says that Thomas found him once, pretending to be a journalist, but he didn't tell his father who he was, or vice versa.
When Oskar starts his search for the Blacks, Grandpa follows him around and ends up talking to one of the Blacks on Staten Island (probably Georgia Black) who tells Grandpa that she just got off the phone with Oskar's mother. (Has she been following him too?)
She wonders why Grandpa doesn't know about the key or the lock.
All the time he's writing this part of the story, Grandpa's letters are getting closer and closer together on the page.
On the way home, at a bookstore, Grandpa thinks he sees Simon Goldberg. The man hugs him and walks away.
Grandpa writes that one time Mr. Black confronted him outside the Empire State Building, wondering why he'd been following them around.
He tells him an abridged version of this confusing story. (Maybe that's why Mr. Black quit the search? There's only room for one old man following Oskar around in this town…)
Finally, we're back to the point where Oskar meets Grandpa (thinking he's the renter. You got all that?).
That night, Grandma and Grandpa have sex again, and later, Oskar throws pebbles at the window, meets Grandpa outside, and tells him about his idea to dig up the grave
After that the text gets too close to read, until it's just one big black square.