Shelley opens with a verdict rather than a story: "That time is dead for ever, child!" We are never told which time it was, what happened in it, or who the child is. The title, "Lines", gives nothing away either. What we get is the aftermath, two people looking back at a stretch of life they can't recover and at the hopes that now haunt them. The central idea is that the loss is double. Time has gone, and the speaker and listener share the blame for what died in it. Those hopes were not taken from them. They were "beguiled / To death".
The first stanza piles up its deaths. "Drowned, frozen, dead" mixes water and ice, as if one kind of ending were not final enough, and "for ever" is hammered out twice in two lines. Then the speaker turns to "the past", and the lines shrink to "And stare aghast". The rhymes crowd together: *past*, *aghast*, *ghast*. The last is a clipped, stripped-down echo of the word before it, so the rhyme seems to stutter, like someone too shaken to finish the sentence. Out of that stammer come the "spectres wailing, pale and ghast", which are the dead hopes themselves. Ghosts are usually dead people, so it is unsettling that here the haunting comes from dead *expectations*. "Beguiled" matters too. To beguile is to charm or deceive, which suggests the hopes were led on and flattered before they were killed. Because the verb is shared between "thou and I", the guilt is shared as well.
The second stanza moves from what died to who is left. The river comes back, but now it is a stream the pair "gazed on", so they were watchers on the bank, not swimmers. Its waves are "unreturning", a heavy negative word that sounds like the water pulling away. Against all this flowing, the next short lines are fixed in place: "we yet stand / In a lone land, / Like tombs". The simile turns the two survivors into stone monuments that exist only to "mark the memory" of what has gone. "Fears" is quietly added to "hopes" here, so what fades is dread as well as dreaming, and the emptiness is complete. Even the verbs ("fade and flee") are things that leave.
The last line, "In the light of life's dim morning", mirrors "life's dark river" from the first stanza. Dark becomes dim, and river becomes morning. Morning is when ghosts are supposed to vanish, so the light seems to dissolve the spectres, which reads as a kind of release. But "dim" refuses real comfort. This is a weak dawn, and the poem does not say whether the morning is the distant youth they remember or the grey present they are stuck in. That ambiguity is worth discussing, because both readings are available and both are sad.
The form helps the mood. Each stanza has seven lines of uneven length, swelling to four beats and shrinking to two, so the verse seems to gasp and recover. In the first stanza the rhymes *child/beguiled* and *ever/river* frame the central trio of rhymes, like walls around a room. The second stanza is looser. "By" has no true partner, and *unreturning* and *morning* rhyme only roughly. You could say the pattern itself is fading, though that is an interpretation, not a certainty.
What makes the poem worth reading is its economy and its honesty. In fourteen lines it sustains one image, the river of life, and never uses it to console. Many poems about loss reach for acceptance by the end, but this one ends on a light that is barely light. It also treats grief as regret, not just sadness. The pain comes from having been present at the death of one's own hopes and being unable to say exactly when or how it happened, only that it did. That sense of looking back at a self that no longer exists is a feeling many readers will recognise, even without knowing the story behind it.