The title tells us what has happened: someone hasn't shown up. The three short lines never state the speaker's hurt, though. We only see a person sitting with a glass of wine, waiting, and a suitcase nearby holding bright red clothes.
That suitcase is the quiet center of the poem. "Portmanteau" is an old-fashioned word for a travelling bag, and it suggests the speaker came ready for a trip or a romantic night. The clothes are "scarlet" and "like feathers," which makes them seem light, showy and a little hopeful, like the plumage a bird puts on to attract a mate. Now they stay packed away, unseen.
The mood is wistful and restrained. The speaker seems to cover disappointment with a drink and a composed surface, and the brightness of the clothes against the empty waiting makes the letdown sharper. Judging by the poem's brevity, the speaker may be keeping a stiff upper lip.