- Marty: "It's a message from Clara, from 1893."
- Jennifer: "Doc's wife?"
- Marty: "She says Doc's in trouble. He vanished... into the future."
- — Marty and Jennifer, as they read Clara's letter
Clara's letter was an urgent message sent through time by Clara Brown in 1893 to Marty McFly in March 1986, to let him know that her husband, Dr. Emmett Brown, had gone missing during an attempt to reach the future.
Like Doc had done with his letter in 1885, Clara sent hers via several generations of Western Union, with instructions that it be delivered to Marty at "the highest attainable level of education prior to university, on the first Monday of March, 1986".
When the Western Union man delivered the letter to Marty during a history class at Hill Valley High School on the aforementioned date, the letter deliverer mentioned to the teacher that his supervisor at Western Union experienced a case like this when he was young.
Dear Mr. Martin McFly,
It is with great consternation I write you this letter; my husband, and your friend, Doctor Emmett Brown, has vanished into the future.
Knowing you live in the future, Mr. McFly, I impose upon you: have you the methods and skill to find my beloved?
I know not how much knowledge you hold on the subject of time travel, or if my husband was the sole repository of this skill... but you are the only one I can turn to.
When you left us, it was to return to your schooling — and I hope my instructions for delivery find you after our adventure together.
Please, Mr. McFly — if there is anything you can do to locate my Emmett, I beseech you do so, if not for my sake, for the sake of the children.
- Back to the Future (IDW Publishing)