I loved the episode, it brought up a lot of unresolved issues such as Woods vendetta with Spike. Spikes past as well as what the song means to him. The episode also had a comeback for Giles, all though unfortunately as a total jackass.
Giles brought back a device, well a stone that burried into the cranium of Spike to find the key to the trigger, the memory. And so the memory was presented before Spike but only the song itself, he had no idea what it meant. That was when Wood talked to Giles about killing Spike because he is a danger, all though Wood just has a personal vendetta.
This is where Giles actually agrees to it, so they set things up and Giles starts to stall Buffy on the cemetary taking up an important issue while doing so. The issue which is "Are you ready to make sacrifices?", she was of course ready to make sacrifices - even so her sister when she was asked.
Meanwhile Wood had trapped Spike in his "crib" with crosses nailed to the walls, and he played the "trigger" song to bring out the beast in Spike. While Spike is revisiting his past Wood is beating the hell outa him, he deals with his past being turning his mother into a vampire and seeing the true beast, the demon of the vampire. Comparing his mother to the demon that now is, how lovely she used to be and how evil she is. She looked down on Spike, and even umh made a 'pass' on him. What boggles me is that Spike was upset by this as a vampire, he almost started crying and then he staked his mother and said "I'm sorry".
Spike wakes up from his visiting in the past and stops Wood from staking him, he then beats the crap outa Wood while explaining how slayers only care about their mission, and he explains how he now learned that it wasnt his mother that told him those things - it was the demon.
Buffy arrives after realizing Giles is stalling her and finds Wood half unconcious having been drained blood, Spike says the words "If he even so much as looks at me funny, I'll kill him". Buffy enters the 'crib' and talks to wood, she says "If you try anything again he'll kill you, but the important thing is..I'll let him".
Ok after a summary of the episode id like to comment on it, I loved how they delt with Woods issues with Spike simultaneously as they delt with his trigger. Giles also showed to BUffy that sacrifices must be made, this is what led her to say that to Wood.
It's good that they cleared these things up cause the next episode I think is the one that starts the finishing story arc, the 5 episode long "battle".