“Oh,” he remembers. “‘A Little Help from My Friends,’ that’s what it’s called.”

John tries to be Sean’s best friend as well as his teacher. John plays him the guitar, and they watch The Muppet Show together—but never the commercials. “Anything you ever see on a commercial is a lie,” John always tells him.

He makes a nighttime ritual for the two of them, flicking the lights off and on in a rhythm that means it’s time to go to bed.

“Good night, Sean,” he says in a soothing voice.

*  *  *

A mysterious letter finds its way to the Dakota on November 29, 1977.

John unseals the envelope with a kitchen knife. He extracts the letter, reaches for his glasses, and reads the first two lines.

WE ARE THE TERRORISTS [FROM] THE FALN PUERTO RICAN INDEPENDENCE MOVEMENT. This letter is a positive (THREAT) to your life.

The group is targeting all three members of the Lennon family. There is also a demand—that John leave $100,000 in a “strong package” at the front entrance to “Dakota House.”

A nine-day countdown is already ticking away.

If John tries “to play any trick to us” by contacting the FBI or the police, the note warns, “we are good preparedly for it.”

John’s pulse starts to race as he runs through his options, seeing none other than to contact the FBI, the US government agency that had previously placed him under surveillance because the Nixon administration didn’t like his politics.

In consultation with the FBI, John decides not to comply with the demands.

On December 19, a second letter arrives, claiming that on the day the cash should have been delivered, “your building was surrounded by 23 armed man’s of our troop,” then acknowledging the holiday season: “This is Christmas time, do your normal life, don’t be afraid is no body outside looking for you, on this you can have our trust.”

The threat, though the FBI can’t identify its source, turns John’s heart to lead.

Now I’ll be looking over my shoulder no matter where I go.

Now it’s no longer safe to go outside.

Now I need to get Yoko and Sean away from the city.

John acts quickly, and in February of 1978 he purchases a thousand acres of land in Delaware County, three hours north of Manhattan. Yoko can look after her latest investment there, a herd of registered Holstein cattle. The dairy cows are prizewinners at the New York State Fair.

“Only Yoko,” John marvels, “could sell a cow for $250,000.”

Even as they reside in the secluded Catskills, thoughts of looming danger cloud John’s mind. He donates $1,000 to the New York Patrolmen’s Benevolent Association so the police can buy bulletproof vests.