Manny, Sid, and Diego's Adventures of Alpha and Omega is an upcoming Ice Age crossover film that is yet to be created.
Humphrey (Justin Long) and Kate (Hayden Panettiere) are two wolves from the same pack in Canada’s Jasper National Park, but on opposite ends of the social order. Kate, the daughter of the Alpha LeaderWinston (Danny Glover) and his mate Eve (Vicki Lewis), is an Alpha herself and takes her duty to the pack seriously. Humphrey on the other hand is the Omega Leader, and spends his days making jokes and playing about with his other Omega friends, Shakey (Kevin Sussman), Salty (Brian Donovan), and Mooch (Eric Price). As the Omega Leader of the Pack, Humphrey is a skilled peace-keeper, but has a crush on Kate, which is against Pack Law: An Alpha and Omega can't mate.
During her youth, Kate left to begin Alpha school with her father. She returns as a fully trained Alpha, but on her first hunt, Claw and Scar, two members of the Eastern pack, ruin her attempt, Manny, Ellie, Sid, Diego, Shira, Crash and Eddie, Peaches, Granny (Sid's Grandmother) and Louis have traveled to Jasper Park Canada and met Kate and Humphrey, leaving her pack with nothing but bones and scraps. The two packs have had a bitter rivalry since Winston dislikes the fact that Tony (Dennis Hopper), the Alpha Leader of the Eastern pack, wants to unite them into one large pack. Winston and Tony meet up one night and arrange for Kate to marry Tony’s son Garth (Chris Carmack). Kate, having followed her father and heard everything, wearily agrees for the good of the pack and she meets Garth at the Howling Rock. Garth is also a fully-trained Alpha, but one thing lets him down: His howl, which is how wolves find their mate, when their howls match. Garth begins to howl, and Kate is mortified by how bad he is. Kate escapes the date for a drink of water and runs into Humphrey by the river along with Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny and Louis. Kate and Humphrey then scream in terror. They are then shot in the butts with tranquilizer darts by a ranger and taken to Idaho.
Humphrey and Kate, Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny and Louis wake up at Sawtooth National Recreation Area and meet a French-Canadian goose named Marcel (Larry Miller) who has an avid interest in golf along with Boog and Elliot. and his caddy, a duck named Paddy (Eric Price). Humphrey and Kate learn that they were relocated to repopulate the species, which upsets Kate. Marcel and Paddy agree to help the wolves return home to Jasper and they hitch a ride in a camper truck driven by a couple that vacation to Jasper yearly while Marcel and Paddy follow from above.
Trouble brews back at Jasper as the two packs discover that Kate has gone missing. Tony warns Winston that on the next full moon if Kate doesn’t return to marry Garth, he and his pack will declare war for their territory.Lilly (Christina Ricci), an Omega wolf who is Kate's younger sister, falls in love with Garth and suggests that she shows him around.
That night, when the camper stops by a truck-stop, Humphrey exits the camper to pee. He is distracted by a cupcake and begins to eat it. A man mistakes Humphrey for a rabid wolf since he has creamy frosting around his mouth. He then prepares to shoot Humphrey, but Kate jumps in to save him. Kate and Humphrey and Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny and Louis escape, but they sacrifice their ride to Jasper.
That night, Kate finds a ravine, which is currently filled up by a mudslide, and tries to cross it. She slips down the cliff, but Humphrey saves her by swinging on a vine and telling her to grab his tail. After that, the duo makes a den for the night.
The next morning, Marcel and Paddy, Boog and Elliot find the wolves with the gang and direct them to a train over a snowy mountain that will take them to Jasper. Climbing the mountain, Humphrey, Sid, Crash, and Eddie meets a bear cub (Maya Feltheimer) who is unfamiliar with wolves. When they're playing, the cub starts to cry when Humphrey throws a snowball at him, and the wolf tries to comfort him. This angers three bears (most likely the cub's parents), who think that Humphrey, Sid, Crash, and Eddie was trying to harm the cub. When Kate, Manny, Ellie, Diego, Shira, Peaches, Granny and Louis realizes that Humphrey, Sid, Crash, and Eddie is in danger, she and the gang rushes in to help them, causing them to slide down the other side of the mountain on a log (which happens to be one of Humphrey's hobbies). Humphrey and the gang saves Kate, and, as the train passes by, the duo manages to get into a boxcar just in time.
On the train that night, Humphrey starts to howl at the full moon and asks Kate to join him. She does, after hearing his voice, and the two howl a romantic duet. Kate realizes that Humphrey is who she belongs with as the others watch, touched. Meanwhile, at the Howling Rock in Jasper, Lilly helps Garth improve his howl. He succeeds and the two howl together. Tony and his pack show up at the scene to prepare to attack the other pack and berates his son for howling with an Omega. Lilly retreats to alert her father. Since Kate has yet to return, Tony commands his pack to take the valley.
Shortly, the train passes by Jasper. Humphrey tries to profess his love for Kate, but the sight of the packs fighting makes Kate jump off the train before he can finish. Kate stops the fight by announcing that she will marry Garth for the good of the packs, much to Humphrey and Lilly's surprise and disappointment.
The next day, a heartbroken Humphrey decides to leave Jasper and travel on his own and shares his goodbyes with Kate, Marcel, and Paddy, Boog and Elliot and the gang, who have arrived and decided to stay so Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny and Louis will take care of Kate and go to the wedding with her. Yet, Kate also feels heartbroken after realizing how she feels about Humphrey. Halfway through Kate and Garth's marriage ceremony, Kate backs out after deciding that Humphrey's who she wants to be with. Garth as well declares the same for Lilly. Winston is confused, while Tony and his pack start to fight the other pack out of anger, but the conflict is cut short when a massive stampede of caribou interrupts the scene. Winston and Tony are trapped in the stampede, so Kate and Humphrey (who has decided to return), both jump in to the rescue along with Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny and Louis. Kate is knocked out when trying to reach cover, and Humphrey rushes forward to protect her, shielding her with his own body while Winston and Tony try to scare the caribou out of the path of the two. After the stampede fades, it appears that Kate has been trampled to death. Humphrey declares his love for Kate and howls as a requiem for her, and all the wolves then join in. Kate then wakes up, much to everyone's relief. Kate and Humphrey finally declare their true feelings to each other, and Winston and Tony agree to unite the packs under a marriage between Garth and Lilly, and demolish the rule over social class. That night, everyone celebrates the happy ending at Howling Rock along with Manny, Ellie, Sid, Diego, Shira, Crash, and Eddie, Peaches, Granny, Louis, Boog and Elliot, and Humphrey and Kate howl a duet at the close of the film.