Two lovers wander late into the night, talking about their feelings and affectionately bickering about what went wrong with their relationship, admitting questionable things from their pasts that no one else would understand, and avoiding the sunlight. Before Sunrise did it first, but The Vampire Lestat injected new blood into the formula. In questioning whether “forever” can be enough time for a pair of lovers, “Montreal” provides an intimate, sensual, and heartbreaking hour of television, the best AMC’s “Vampire Chronicles” adaptation has produced yet. Jacob Anderson and Sam Reid’s vibrant chemistry grounds a penultimate episode that’s contradictory in its triumphs: This is simultaneously the series’ cozily romantic zenith and the clearest case for why Louis and Lestat should not be together.