This is the last level of the prologue. Your team is facing Cia's army head on. Any currently available characters might be useful but it would be worth it to use Lana for the first time.
Looking for the boomerang
Now that you know the drill, take down any available bases and checkpoint guards to slow the enemy down. Wait until the north-east base is open. Make sure to collect the boomerang, as it's the only thing that can take down the moving vines.
Another giant monster?!
Cia will launch another monster onto the battlefield. If you remember the monster's appearance in Ocarina of Time and perhaps The Wind Waker, the idea here is the same: wait until the deku heads come out. Make sure to use the boomerang on all heads because taking on only one or two will increase the time you take to reach the weak point. At some point, the monster will separate itself; just find the real monster and do it all again to defeat it.
Worlds colliding
Now go to Cia's base and go at her completely, attacking her until her health points are drained. In a cutscene, Cia disappears and the group splits up into three worlds. Veterans of the series should recognize the games and their respective consoles; Impa and Sheik go to Ocarina of Time, first released on Nintendo 64. Lana goes to Twilight Princess, the last game on Nintendo GameCube and the first of the series released on Nintendo Wii. Link himself goes to Skyward Sword, released only on Nintendo Wii.