Hankies will be in abundance at movie theaters this weekend with the opening of “Dear John,” the latest weeper based on a Nicholas Sparks novel, the man who has unleashed “A Walk to Remember” and “The Notebook” on the world. Those who long for their emotions to be tantalized, pummeled and altogether manipulated have a dear friend in Sparks, who knows how to pile on the maudlin tragedy like nobody else.

This time, the setting is Charleston, S.C., around the turn of the 21st century. Army Special Forces member John Tyree (Channing Tatum, “Fighting”) is home on leave and meets cute with college girl Savannah Curtis (Amanda Seyfried, “Jennifer’s Body”) when he jumps off a pier to retrieve her purse from the ocean.

The two ensuing weeks they share together are full of idyllic clichés: the makeout session in the pouring rain, the moon they’ll both be able to see from wherever they are , and John finds himself falling in easily with Savannah and her friends, including Tim (Henry Thomas, “Don’t Look Up”), who has an autistic son who adores Savannah.

All of it gives John an excuse to avoid his father (Richard Jenkins, “Burn After Reading”), a shy, awkward man who finds solace in his large coin collection, a hobby he used to share with John.

Soon enough, John is back overseas, but he and Savannah are committed to staying connected through frequent letter writing, a vehicle that gives the film more than its fair share of montages. He has less than a year left in his deployment, and the two will be back together soon — a plan that hits a wall when the Sept. 11 terrorist attacks hit and military members all over feel the duty to reenlist.

The film finds somewhat of a footing with this grounding in real-life events, but it rarely feels like more than a plot device. It could have been Sept. 11 or it could have been any fictional event that put him in a difficult position. Real-world subtext never makes an appearance.

Up until this point in the film, it feels like a remarkably restrained affair from the Jamie Linden script based on the Sparks novel and the direction of Lasse Hallström, who has his own predisposition for sentimentality.

The relationship between John and his father plays a large part in the narrative, and it’s a pleasure to see the wonderful character actor Jenkins get far more face time than a movie like this tends to give its supporting players.

Still, the third act schmaltziness eventually shows up, and it’s a flood of stroke, cancer and broken hearts that returns the audience to familiar Sparks territory — a welcome relief for his fans, no doubt.

While Tatum — whose acting skills are often overshadowed by his heartthrob image — gives us a character to care about, Seyfried’s primary talents come into view in a short segment where she sings. As a dramatic actor, she looks lost half the time.

Either way, the two are set adrift in a sea of sap the film tries to carefully balance with several unfocused war sequences to make it semibearable for the guys who are dragged there by their Valentine’s dates. Too bad romance is the one area where the film categorically fails — the most moving scene has Savannah out of sight and mind.

“Dear John” will preach to the choir quite capably; others should just return to sender.