The Choices of Master Samwise - Sam, seeing Shelob has Frodo, attacks her. Shelob is fierce, but Sam holds up the phial of Galadriel and cries out the words in Elvish. This finally chases Shelob off, but when Sam checks to see how Frodo is, Frodo is cold and lifeless. Convinced Frodo is dead, Sam takes the Ring and vows to finish Frodo's quest on his own.
As Sam goes off alone, he hears Orc voices, and not knowing what else to do, puts on the Ring in order to become invisible. Sam hears the Orcs carrying Frodo's body away. He also learns, by eavesdropping on the Orcs, that Gollum is a known accomplice of Shelob's and often lures others to her lair for her to eat.
Worst of all, he learns Frodo is not actually dead, but simply paralyzed and in a death-like state due to Shelob's poison. As these terrible truths sink in, the Orcs enter their tower and shut the door, taking Frodo with them and locking Sam out.