The trail to Lake Serene is a steep, busy and beautiful trail to a lake that lives up to its name.

The trailhead is easy to find, marked by a large gate across it. Near here is a helpful map, describing the trail. Walk past the gate and onto a long-abandoned road, closed to vehicles. Walk it through great alders, birches and pines. You'll soon intersect a jeep track coming up from the left, also closed to vehicles. The old road soon ends at a clearing.
There's a neat side-trip here, to the old Honeymoon Mine. For it, go right, into the clearing. A narrow path leads to the mine, with a fascinating (relatively safe) tunnel to poke around in.

Back at the clearing, find the trail to your left-ish. The creek you'll come to is an easy ford, but better is an extremely muddy-slippery path to the rickety bridge. Once across, the trail (actually an ancient mining road) winds up the creek valley, in great second-growth trees, usually in earshot of the nice brook.

Soon, you will come to a junction. The right fork switchbacks about 6 times, and up stairs to Bridal Veil Falls, a gigantic, billowing waterfall plunging over huge granite cliffs. More switchbacks down lead back to the junction.

From its left fork, the trail dips down to a long bridge over gorgeous, spaying Lower Bridal Veil Falls. It winds on to a smaller creek/falls crossing. (It's bridgeless; be careful when crossing mossy rocks.) From here, the trail switchbacks up and up and up, in old-growth forest. There are great views to the Skykomish Valley and Monte Cristo area peaks along the way. The trail climbs very steeply up stairs and switchbacks (28, count 'em!) until finally flattening out on rock filled cribbing, with views down to the woods where you came from. The trail goes over a small hill to beautiful, sparkling,(or maybe fog-filled), Lake Serene. It really is, too!

At the lake, look up-up-up-up--(keep going!) to the towering summit of Mount Index. Be sure to take lots of pictures!