Lyra realises that Sir Charles is Lord Boreal, originally from her own world, and Will hears news of his father, who had disappeared after discovering a window between the worlds. Will and Lyra escape back to Cittàgazze with the alethiometer and are rescued from marauding children by Serafina Pekkala.

Why did Lyra get the alethiometer?

When the Master of Jordan College proposed that Lyra go to live with Mrs Coulter, Lyra was very excited. Before she left, the Master gave her an alethiometer, letting her know it was extremely important that Mrs Coulter never saw it.

What happens to Lyra at the end of His Dark Materials?

In the final novel, Will and Lyra discover that there is a land of the dead after Lyra continues to have dreams about Roger trapped there. Promising to help him, she and Will journey there by using the subtle knife. However, Lyra is forced to leave Pantalaimon behind, causing her immense pain.