This is twentieth and final story mission in Destiny. You've reached The Black Garden. Now it's time to destroy its heart.
Vex surround the portal, including Goblins, several Minotaurs, and a Hydra. Try to take down the Hydra before moving onto the Minotaurs to avoid the constant blasts of the Hydra.
With the enemies defeated...
...approach the giant portal to get sucked into The Black Garden.
The Black Garden is a series of rooms and areas filled with grassy areas and block rock formations.
Follow the path to see Vex Goblins frozen in some kind of stasis. Keep moving forward until you reach a hall full of frozen Goblins.
Towards the end of the hallway are four Goblins waiting to ambush you. A Minotaur and two Harpy enemies will also appear.
Defeat them and keep moving, fighting off any more enemies that get in your way. The next room will throw some more Harpy enemies at you. Take 'em out and keep going. From here, you'll keep running into enemies, but keep heading forwards.
Once you enter the Darkness Zone, you'll find yourself outside and in full view of the garden. Take a moment to breathe it all in.
Run to the right and you fight off some more Vex, including another Cyclops. Head back inside by following your waypoint.
Inside you'll find an enemy known as the Divisive Mind. It shoots out powerful blasts, but it's no big deal. It's basically a stronger version of a Hydra.
Clear out the room and head back outside and into the next area.
Time to descend deeper into the garden. Run down the steps and start taking down the Hobgoblins patrolling the area.
When you reach the next main area, you'll be tasked with scanning two Vex clusters, both of which are on either sides of the area. Vex enemies are swarming the entire place, so your best option is to pick one of the clusters and start pinning down each enemy one by one.
With both clusters scanned, head for the main entrance into the next area,
And open the giant door as a Gate Lord.
Enter the next room to find the heart of The Black Garden.
Now that all the Vex haven awoken from their deep worship, wipe them out! After the last one is killed, the heart will summon one of the three giant statues in the area. Your next goal will be to fight off each of the three Minds separately.
The Eschaton Mind won't wander past the main area near the heart, so using the giant blocks and walls for cover is an ideal strategy. You can pelt the giant with ease from this spot, but the real challenge will come in trying to attack the monster while managing all the other Vex that come to attack.
The next giant is the Imminent Mind,
And the same strategy should be used here.
The same goes for the final giant, the Primeval Mind.
Minotaurs will come with the final giant.
With all three giants destroyed and all the other remaining Vex taken care of, the heart of The Black Garden will explode, leaving behind lovely rose pedals.
The mission is over and the heart is gone! Congratulations! You've completed the game! WOO-HOO!!!