The sonnet opens with the narrator explaining how he has been dazzled by the eyes of the lady. There is no defense against their bewitching ‘sparks’ which have penetrated his heart, but without damage. He is overcome with the power of her gaze and experiences 'quaking pleasure’. He is overwhelmed to the point of confusion, and feels as if he has been struck by lightning. He appears to stumble and flail in the light, and calls for help as he has lost his bearing. He does begin to feel pain as he falls, but bears the discomfort with fortitude. He realizes that the light which has enchanted him is followed by the deadly rumble of thunder.
The sonnet uses a variety of types of light to describe the gaze of the lady. The light is initially ‘sparks’, which could be said to wane as quickly as they appear. Even these brief flashes cause the narrator to seek cover; which he does not find. The sparks pierce his heart, but, at this point, do not damage it. Feeling the need to take cover should indicate that the narrator will not be able to stand a harsher radiance. Her love is then compared to sunbeams, but the ‘vehemence’ or harshness goes beyond the gentle warmth of an English summer’s day. He is overcome by this, as if stunned by a bolt of lightning. The lightning comparison sees him weak and defenseless - blind, disoriented and confused. The narrator bears the strike with fortitude, and awaits the inevitable ‘fearful’ consequences of his love; as thunder follows lightning, so there may be ‘deadly’ penalties for this relationship. These are clever allusions to the condition of love as would be appreciated by the Tudor court; an initial attraction may lead to love, which may in turn lead to vulnerability and public shame or social weakness.
Wyatt flexes the structure of the sonnet here as the division between the sestet and the octave is organized through the use of caesura and enjambment in line 8. This enhances the proximity of one idea to the other. This idea is echoed in the metaphors used as the closer that lightning is to thunder, the more dangerous the consequences are.