Pairing: Commander Shepard/Garrus Vakarian
Fic Title: The Hundred Year Distance
Link: Here @ FFN
Rating/Warning(s): M for sexual content. Also, it features a human/alien pairing, so steer clear if xenophilia's not your thing.
Why This Must Be Read: Mass Effect 3 isn't coming out until early 2012, so nobody knows yet just how Shepard's story is going to end. But if I could choose the perfect finale for my Shepard and Garrus, this fic would be it. It's poignant and bittersweet, and the author captures both characters beautifully while doing a fantastic job of portraying the depth and endurance of their relationship. I've read this fic multiple times, and it still gets me misty-eyed with each reading.