A helicopter dad nearly spins out of control as his sons struggle to master the knuckleball—and perhaps save baseball’s most storied pitch from extinction. The knuckleball is the only skill that can elevate an athlete without a superjock’s speed, strength, or explosive power to the Hall of Fame. Thrown without spin, it darts around unpredictably for reasons physicists and engineers labor to explain. It’s a secret weapon every pitcher should want to master, so why is the knuckleball close to extinction? When a father discovers his baseball-crazed sons have the knack for the knuck, they begin a decade-long, cross-country quest to perfect the pitch. Along the way they meet the greatest to throw it, the scientists investigating its mysterious movement, sabermetricians, and executives who hope to resurrect it. The aspiring knucklers also learn lessons they’ll use off the field, proving that when life throws them curves, they have something to throw back.