This is the opening of the first arc, called Gold Silver, the song is the translation of Biggest Dreamer:

Wanna be the biggest dreamer

(Artur is with Dracomon looking up)

Running full speed through

(Lucas P rides Liamon full speed in a large plane)

both the future and the present

(Juca is seen with Wormmon snoozing below the shade of a tree)

That's right, I've realized it,

(Maria and Penmon are in the beach, both playing in the water)

I forgot to do my homework

(Ana and Dobermon cross a city filled of rookie digimon)

That's one puzzle, puzzle, puzzle,

(Eric and Wizarmon are reading in a library)

"Who am I?"

(Marcio and YukiAgumon are going through the tundra)

Even if I slide

(They all look to the same direction and rush there)

and skin my knees

(Marcio trips, YukiAgumon helps him up)

I've gotta stand right back up,

(Marcio stands up as they keep running)

I know my chance will run away

(Artur rushes forward in determination, Dracomon behind him)

Big and bigger, biggest dreamer!

(Dracomon glows as Artur now rides Coredramon(Blue) through the skies)

Dreaming is the start of everything

(Penmon glows as Maria rides on Saberdramon just Sora rode Birdramon)

that's the answer

(Wizarmon teleports himself and Eric)

I'll fly farther than anyone

(Wormmon also evolves as Kuwagamon carries Juca on his back)

through all the tomorrows

(Marcio rides Seadramon)

Fly to the horizon,

(Coredramon goes faster as they meet with the others)

our courage has gained wings

(Coredramon growls as they now see Orgemon, Fugamon and Hyogamon, their respective armies(Goburimon, Shamanmon and SnowGoburimon) behind them)

In order to grow big and strong,

(The team kicks serious digital ONI butt)

I'll run too

(Coredramon glows as he changes to green and fires Green Flare Breath)

For a long time

(Saberdramon and Kuwagamon erase Fugamon)

I've heard the count down

(Seadramon and Wizarmon finish off Hyogamon)

I'm prepared,

(Coredramon and Liamon destroy Orgemon)

let's start now, change into zero!

(They see Gold & Silver mountain)

Big and bigger, biggest dreamer!

(Coredramon goes back to blue as they ride him or Saberdramon)

We've gotta believe,

(The silver silhouette of Ginkakumon and the golden silhouette of Kinkakumon are seen)

disappear into the twinkling instand

(The image zooms out to show Bit Island)

I'll run, not turning away from my heart's target,

(Coredramon roars as Leomon, Garurumon, BlackGarurumon, Meramon, etc join them to the final battle)

through all the tomorrows

(Liamon, with Garurumon and BlackGarurumon behind him face off some SnowGoburimon)

Big and bigger, biggest dreamer!

(Coredramon(Blue), Meramon and Leomon blast Shamanmons)

Dreaming is the start of everything

(Kuwagamon and the rest deletes Goburimons)

that's the answer

(The image of every one of their partners is seen in the screen in their normal levels firing their signature attacks)

I'll fly farther than anyone

(Coredramon, Saberdramon and Kuwagamon cross the skies)

through all the tomorrows

(The team watches them, smiling)

Big and bigger, biggest dreamer!

(Artur looks at the Blue Diamante and Green Malachite)

Dreaming is the start of everything

(Dorulumon, Leomon and Patamon are seen on a cliff)

that's the answer

(Leomon calls them as they walk away)

I'll fly farther than anyone

(Artur now rode Coredramon to the sunset)

through all the tomorrows

(Ana and Dobermon watch the sunset from a beach)

Big and bigger, biggest dreamer!

(The others are seen running for the sunset)

Dreaming is the start of everything,

(The team is united watching the sunset)

that's the answer

(Artur has a smirk as he looks up)

Wanna be the biggest dreamer

(Dracomon also looks up)

Running full speed through

(Everyone looks determined as they grip their digivices)

both the future and the present

(The logo appears as the episode begins...)