As destiny would have it, Snoopy receives an unexpected message from Lila, a young girl who has been confined to her hospital room for a staggering three weeks. Her days are filled with the dullness of illness and isolation, making her heartfelt plea for companionship resonate deeply within Snoopy's brave heart. Inspired, he embarks on a daring adventure with his loyal companion, Woodstock, while Charlie Brown remains blissfully in the dark about the true identity of this enigmatic Lila.
To everyone's astonishment, Lila turns out to be Snoopy's original owner, a revelation that sends the ever-curious Linus racing to uncover the details. The shockwaves of this revelation reverberate throughout the Peanuts gang, leaving Charlie Brown in a state of stunned silence as he comes to terms with the profound connection Snoopy has with this long-lost friend.
Despite the countless "No Dogs Allowed" signs littering their path, Snoopy and Woodstock face a whirlwind of amusing misadventures. They encounter a spirited romance with a young animal enthusiast named Clara, whose reluctant mother eventually allows her to adopt Snoopy as her pet. Their escapades also take them on a camping journey where they happily play football, create music, and whip up delicious meals together.
After navigating through a maze of bureaucratic hurdles, the adventurous pair finally reaches Lila's hospital room, only to find that dogs are prohibited once again. Snoopy's first attempt to stealthily enter Lila's room is thwarted, but in a twist of fortune, he succeeds on his second try, managing to bring joy back to her face through his presence.
As their bittersweet visit nears its end, Lila urges Snoopy to stay with her, but he finds himself conflicted, torn between his unwavering loyalty to Charlie Brown and his rekindled friendship with Lila. Ultimately, he chooses to return to Charlie Brown, but Lila's tears of longing pierce his heart and compel him to turn back for an emotional farewell.
Before departing, Snoopy pens a touching letter, distributing his cherished possessions among his Peanuts pals: Linus is entrusted with the croquet set and chess pieces, while Schroeder receives the prized record collection. However, Charlie Brown is left with nothing but a warm, heartfelt wish from his dear friend.
The Peanuts gang gathers to say their goodbyes, showering Snoopy with bone-shaped gifts, all the while wearing tear-filled expressions. As each friend steps forward to pay tribute to their beloved companion, Charlie Brown's emotions boil over, leaving him speechless as he attempts to offer his own special gift. In the aftermath of Snoopy's poignant departure, Charlie Brown finds himself unable to eat or sleep, as the ache of loss slowly consumes him.
On his way back home, Snoopy encounters an unexpected yet delightful challenge: a "No dogs allowed" sign glaringly posted outside Lila's apartment building. His eyes twinkle with joy as he recognizes this sign could serve as the ideal pretext to reunite with his dear friend Charlie Brown. Upon his arrival, Snoopy meets Lila's feline roommate, a regal cat who seems almost amused by the dog's excitement. Undeterred by the feline's presence, Snoopy proudly showcases the sign, leaving Lila with no option but to allow him to leave. Treading cheerfully, Snoopy hurries back to Charlie Brown, thrilled at the prospect of rekindling their cherished bond.
Upon returning home, the children burst with joy at Snoopy's cheerful presence and promptly hoist him onto a pedestal, cautiously transporting him to his doghouse. Once settled, Snoopy eagerly seizes his trusty typewriter and begins dictating demands to his friends, insisting on the return of the various items he had previously loaned them. Growing increasingly frustrated by this sudden reversal of roles, the kids, with a collective sigh, decide to leave Charlie Brown and Snoopy behind, leading to feelings of solitude and abandonment for both of them.
