I found this very interesting read over here. It's the Magic story-line condenced. I should have written something like this myself. I remember many a night in a parking lot after a draft explaining it to someone.
Chapter One: Yawgmoth and The ThranOn the plane of Dominaria, long before the five colors of Magic were mastered, a civilization known as the Thran made powerful artifacts fueled by magical Powerstones. These stones were eventually found to give people diseases, so they called in Yawgmoth, a eugenicist and disease specialist who had previously been exiled. Yawgmoth cured the disease and rose to great power in doing so, but it was soon discovered that during his exile, he committed horrific acts in the name of studying disease. A civil war broke out between Yawgmoth’s supporters and the people who knew the truth about him, and Yawgmoth realized his time with the Thran was nearing its end. Yawgmoth saw an opportunity when a Planeswalker named Dyfed visited Dominaria. Planeswalkers, as you may or may not know, are individuals of immense magical power and talent who have the ability to travel between planes at will. Yawgmoth tricked Dyfed and convinced her to find him a new plane to call home. Dyfed found Phyrexia, a metal world of nine nested spheres that its original creator had abandoned. She constructed a portal there and brought Yawgmoth, who populated it with his own followers and began reshaping the plane to his vision. Eventually Dyfed realized Yawgmoth was up to no good, but the damage was done. Yawgmoth had turned Phyrexia into a Machine Undeath Hell World, and his followers had become horrific mutated amalgamations of twisted metal and decaying flesh. Yawgmoth sent his army through the portal to crush the Thran, and was horribly successful. The Thran were able to seal the Phyrexian portal with a Powerstone, but their civilization was already doomed to extinction. Dominaria was safe from the Phyrexian threat... for now.
Chapter Two: Urza and the Phyrexian InvasionA young Urza and Mishra holding their Powerstone halves The Phyrexian portal laid undiscovered for eons until it was found by two archaeologist brothers, Urza and Mishra. They removed the portal’s Powerstone, breaking it in half and each keeping one piece for themselves. This began The Brothers’ War, in which both Urza and Mishra built armies, studied magic, and constructed deadly artifacts in a bloody struggle for both halves of the stone. Further complicating matters was Yawgmoth, who became aware that the portal was once again active and sent troops through to infiltrate both sides of the war. Eventually, there came a final climactic battle between the two brothers. Urza injured Mishra during this battle, and in his wound Urza saw that Mishra had replaced parts of his body with machinery, like the Phyrexian infiltrators. He blamed the Phyrexians for the tragic war against his brother and flew into a rage, activating an artifact of immense power and destroying both his and his brother’s armies. The explosion destroyed the Phyrexian portal and caused Urza to ascend, becoming a planeswalker with his eyes replaced by the two halves of the Powerstone.
Urza left the plane of Dominaria and began his centuries-long preparation for his war against the Phyrexians. He developed the Legacy Weapon, a device powered by several powerful artifacts including the Powerstone, a silver golem named Karn, and Gerrard, a human heir Urza engineered with a multi-generational breeding project. Meanwhile, Yawgmoth had built an artificial plane called Rath and started loading his armies onto it, with the intention of merging the plane with Dominaria and therefore bringing his entire force there at once. After lifetimes of planning, the Phyrexian Invasion began. Yawgmoth overlayed Rath onto Dominaria, and the full extent of the Phyrexian horror arrived on the plane. Urza and Gerrard were eventually captured by the Phyrexians and forced to fight each other in arena combat, during which Gerrard decapitated Urza. Gerrard escaped Phyrexia with Urza’s head and reunited with Karn, shoving Urza’s Powerstone eyes into Karn’s chest and completing the Legacy Weapon. The blast destroyed Yawgmoth, consumed Gerrard, ended the war, and caused Karn to ascend and become a Planeswalker. Dominaria was ravaged, but once again safe from Phyrexia.
Chapter Three: Karn Tries To Fix EverythingDevastated after the horrors he had witnessed during the war, Karn used his newfound Planeswalker powers to create a plane of his own vision: Argentum, a world made entirely of metal. The depressed Karn lingered on his plane in a self-imposed exile, but still sent out probes to keep tabs on Dominaria. One probe, however, was flawed, and became the Mirari, a magical orb with the ability to grant the deepest desires of its user. To make a long story short, the Mirari was not good for Dominaria and led to the creation of a demigod and yet another continent-engulfing apocalypse. When Karn became aware of this, he returned to Dominaria to retrieve his creation. He brought the Mirari to Argentum and turned it into a robotic guardian named Memnarch. Tasking it with protecting the plane Karn had created, Karn set out to explore the Multiverse. Meanwhile, Memnarch slowly became corrupted by traces of Phyrexian oil Karn had unknowingly brought with him to Argentum. He went insane and reshaped the world according to his vision, naming it Mirrodin. Karn had to come back and undo the damage he caused (again), turning Memnarch back into the Mirari. It was about this point that Dominaria was starting to feel the strain from all the cataclysms that had happened there over the millennia. Rifts in time and space started appearing, causing strange disturbances throughout the plane. Karn teamed up with a bunch of other Planeswalkers to mend the rifts, each of them giving up their Planeswalker powers to seal the rifts in an event known as The Mending.
With the last of his Planeswalker powers, Karn flung himself back to Mirrodin, but he did not like what he had found. The same Phyrexian oil that had taken control of Memnarch was seeping into the rest of the plane, and a new Phyrexian menace was beginning to emerge. These Phyrexians trapped Karn in the core of the plane, declaring him the Father of Machines and tormenting his mind with their demented whispers. On the surface, a war was beginning to break out between the citizens of Mirrodin and these twisted abominations that had appeared. Mirrodin, being made entirely of metal, was a fantastic breeding ground for the Phyrexians, and they were winning the war. A Mirran Planeswalker named Koth recruited two other planeswalkers, Elspeth and Venser, to help him fight the war. Elspeth had faced the Phyrexians before on her home plane, and Venser had helped Karn seal the portals during the Mending. The three journeyed to the center of Mirrodin in search of Karn, and found him driven nearly insane by the Phyrexians. Venser nobly sacrificed his life to transfer his Planeswalker powers to Karn, purifying him of the Phyrexian corruption and restoring him to Planeswalker status. But, once again, the damage was done. Koth, Karn, and Elspeth returned to the surface to find Phyrexia had overrun the plane, turned almost every being into their corrupted vision of life, and declared Mirrodin was now New Phyrexia. Devastated by guilt, overwhelmed with fear, and weary from battle, Karn and Elspeth fled the plane to recover and gather support for yet another Phyrexian war. Koth remained, and continues to fight for his home world to this day.
Chapter Four: Bolas and The EldraziBefore the Mending, Planeswalkers were essentially gods. They lived forever, could change their appearance at will, and had near-limitless powers. The Mending took away the majority of that power, leaving Planeswalkers the ability to travel from plane to plane at will but otherwise making them no more than very talented wizards. Nicol Bolas, a dragon Planeswalker who had lived an exceptionally long time, was not pleased at this development, and dedicated himself to doing whatever it took to restore his former powers. Being an ancient dragon of unmatchable patience and intelligence, his plans were intricate, manipulative, and eon-spanning. The most devastating of these plans was the release of the three Eldrazi Titans.
Many millennia ago, the Eldrazi Titans Emrakul, Kozilek, and Ulamog roamed the Multiverse, all-powerful and ever-hungry. They would arrive on a plane, devour its energy and inhabitants, and promptly leave for the next one. The spirit dragon Planeswalker Ugin recognized their threat to the Multiverse and, fearing they couldn’t be killed, decided to trap them to one plane, endangering the plane but sparing the Multiverse. With the help of two other Planeswalkers, the vampire Sorin and the lithomancer Nahiri, Ugin rendered the Eldrazi inert and bound them to the plane of Zendikar, where they would stay for 6000 years and eventually be forgotten. But Bolas did not forget. He tricked three other Planeswalkers into releasing the seal on Zendikar, reviving the Eldrazi and once again threatening the Multiverse. This brings us into the current Khans of Tarkir storyline; Sorin has returned to Ugin’s home plane, Tarkir, to get his help in binding the Eldrazi once more. Unfortunately, he only found the bitter revelation that Ugin was dead, put in his grave by none other than Nicol Bolas.  11/06/14