This episode perfectly sets up a three-pronged cliffhanger heading into the Season 1 finale: the completion of the antenna, the bottom of the basement hole, and Boyd's survival in the deep forest.
At Colony House, the weight of survival becomes too much. Eric tragically takes his own life, causing the usually unshakeable Donna to completely unravel. [S1E9] Into the Woods
Pushing further into the dense woods than anyone has ever dared, Boyd and Sara find a tree adorned with clinking glass bottles. Inside one, they find a slip of paper dated "1865". This episode perfectly sets up a three-pronged cliffhanger