The adventure starts at Pride Rock in Africa, where herds of countless animals, and the Future Time Travel Squadron gather around to celebrate the birth a newborn lion cub, Simba, of King Mufasa and Queen Sarabi. The only citizen who is not happy about this is Scar, King Mufasa's younger brother, who longed to have the throne to himself.
Overtime, Simba grows into a young cub and, along with the FT squad, learns about everything about the Pride Lands, and that includes the outlands, which Mufasa says is strictly prohibited for Simba to enter. When Scar tells Simba about the elephant graveyard in the Outlands, Simba, along with his best friend, Nala, (along with the FT Squad) outsmart Mufasa's majordomo, Zazu, and venture into the graveyard, where they encounter three hyenas, Shenzi, Banzai and Ed, who attempt to kill them. Thankfully Mufasa (who had been warned by Zazu) arrives and saves the cubs, along with Kyle. Later that night, after Mufasa orders Zazu to escort Nala home, and Kyle and his team to go home to Lake Hoohaw, he gives Simba an emotional lesson about bravery and valor and that he'll always be there for him.
Meanwhile in the elephant graveyard, Scar scolds the hyenas for failing, but also reveals his plot to kill Simba and Mufasa, so that he can have the throne and that the hyenas will never go hungry again.
The next day, at Lake Hoohaw, Kyle, out of guilt and sorrow over what happened the day before, decides to make things better for Simba and Mufasa and flies back to the Pride Lands, where he joins Simba and Scar walking into a deep gorge. After being told by Scar to stay on a rock under a tree, Scar leaves the scene and orders the hyenas to ignite a wildebeest stampede in the gorge. Simba and Kyle run for their lives, but are saved by Mufasa and the rest of the FT squad, who followed Kyle shortly after he left in the early morning. While Simba, Kyle and the rest of the squad are put on a rock above the raging stampede, Mufasa climbs up a high cliff, where Scar betrays and throws him back into the stampede, where he is killed. Simba and the others find Mufasa's dead body and mourn in deep sadness. Scar arrives and tricks Simba into thinking that he was responsible for his father's demise. Due to the shame of a terrible act, Scar encourages Simba to run away and never come back, which he does. The FT Squad finds it crazy, but after Scar brings up Kyle's weakness of disappointing his close loved ones, they rush after Simba but vow that Simba is innocent and will return someday. Once they vanish, Scar orders the hyenas to kill them. After a chase, Simba and the others get away, but Kyle gets seperated and Cassidy gets her wings hurt. With Simba's absence, the hyenas decide to let Scar think that Simba and the others have been killed and turn around to report back to Scar. Scar then assumes the throne and things begin to change in the Pride Lands.
Kyle, having fainted after escaping the hyenas is found by a mysterious fellow who takes him and rushes off into the distant desert. As for the rest of the squad, they tend to Cassidy's wounds easily, but worry about Kyle and Simba's safety. As for Simba, he collapses in the desert and is almost eaten by scavenging vultures. Before that happens, the birds are scared off by a meerkat named Timon, a warthog named Pumbaa, and a group of anthropomorphic animals named Falco Lombardi, Peppy Hare and Slippy Toad. Shortly after deciding to take Simba under their wing, they are joined by the same person who helped Kyle earlier, who reveals himself as Fox McCloud, the leader of the Star Fox team, which consists of himself, Falco, Peppy and Slippy. The rest of the squad joins up with them shortly after. Timon and Pumbaa then teach Simba about their philosophy, "Hakuna Matata" which means no worries. Years later, Simba, once an adult, comes to Timon, Pumbaa and Slippy's rescue when they are attacked by a lioness. However, after a brief conflict, Simba discovers that it is Nala. Nala expresses her delight of Simba being alive, but later questions Simba for not coming back to Pride Rock. She also says that under Scar's rule, the Pride Lands have turned into a barren wasteland, with no food or water to support the pride. Still driven guilty by supposedly causing his father's death, Simba refuses and leaves. Meanwhile, Kyle reveals his own problems to his girlfriend, Kaytlin. He says that ever since Timon and Pumbaa took Simba under their wing, Kyle has not stopped thinking about Simba's destiny, but never revealed it out of fear of making him depressed like he was when Mufasa died. Kyle sadly assumes the worst of what the rest of the team will think of him and goes to find Simba. When he does, they are both encountered by a wise, yet crazy baboon, Rafiki, who tells Simba that Mufasa will continue to live in him. After being told to take his place in the circle of life by his father's ghost, Simba beings his journey back to Pride Rock along with Kyle.
Upon arrival, Simba and Kyle are horrified at what Scar has done to the land. Nala, Timon, Pumbaa, Fox, Falco, Peppy, Slippy and the FT Squad also arrive on the scene. In doing so, they reveal to Kyle that they are not mad at Kyle at all for keeping Simba's destiny a secret. They say that Kyle was simply allowing Simba to take his time to put the past behind him. Fox also reminds Kyle that he had lost his father when he was young, but he put it behind him. With everything sorted out, the heroes proceed to Pride Rock. While Timon and Pumbaa distract the hyenas, Simba confronts Scar on Pride Rock after Scar strikes Sarabi in the face. Scar turns the tables by revealing that Simba caused Mufasa's death, and forces Simba over Pride Rock's edge, where Simba holds on for his life. Believing that he has won, Scar quietly reveals that he killed Mufasa. Enraged, Simba leaps back and pins Scar to the ground, forcing him to tell the truth to the pride. A violent battle erupts between the hyenas and the lionesses, the FT Squad, the Star Fox team, Timon, Pumbaa, Rafiki, and Zazu. As the battles rages, Simba confronts Scar alone on top of Pride Rock. Scar begs for mercy and blames everything on the hyenas. Not wanting to become the murderer that Scar was, Simba spares Scar's life and exiles him. Scar refuses and fights back. A one on one battle begins with Simba winning after throwing Scar over Pride Rock. Scar survives the fall but is immediately killed by the hyenas who overheard Scar's treachery.
With Scar defeated and the hyenas banished, the battle ceases and Simba becomes the new king of Pride Rock. Peace is brought back to the land and Rafiki introduces Simba and Nala's newborn cub to the gathering herds of animals. As for the FT Squad, they go back to Lake Hoohaw, while Star Fox returns to their home galaxy, the Lylat System, but not before Kyle gives Star Fox honorary Future Time Travel badges for helping them achieve success in their mission. Fox then encourages the squad that there are plenty of other adventures yet to come and he promises them that they will meet again.
- Fox McCloud, Falco Lombardi, Peppy Hare and Slippy Toad guest star in this adventure.
- Peanut, Butter and Jelly Otter make minor guest appearances in this adventure.
- This is the first adventure story with all six members coming together.
- The FT Squad returned to the Pride Lands in The FT Squad's Adventures in The Lion King 2: Simba's Pride.
- There are some stories that occured before this one, but they are stories revolving around one or two of the FT Squad original members. Some of these are part of The FT Squad Chronicles.
- Kylgrv was born the same year The Lion King came out; 1994.
- Kylgrv dedicates this story to everyone who inspired over the years of when he was watching crossovers. The people who receive dedication include FantasyFilms2011, LionHeartCaptain, LionKingRulezAgain, FusionAngelFuAn (the four founders of the LionKingHeart Fantasy Films Crew), and many more.
- Originally, the Star Fox team was not going to appear in this crossover story, but Kylgrv chose to add them so that in the future he can do a crossover film with The Lion King 1 1/2.
- Kylgrv chose the Star Fox team as guest stars because he thought that Simba and Fox share a similar tragedy. Both of their fathers were killed by their archenemies. Simba lost his father to Scar and Fox lost his father to Andross.
- Kylgrv was born in 1994, the same year The Lion King was released in theaters for the first time.
- The Star Fox franchise began in 1993, but Star Fox 64, released in 1997, was the true inspiration to add Star Fox in this movie.
- Star Fox's Adventures in The Lion King 1 1/2 is a parallel story to this one.