Prophase II is the first step of meiosis II, which is a mitotic division of each of the haploid cells produced in meiosis I. During prophase II, the chromosomes condense, and a new set of spindle fibers forms. The chromosomes begin moving toward the equator of the cell. The key events that occur during prophase II are:

• Chromosomes condense: Chromatin first condenses into chromatids, and then more tightly into chromosomes.
• Nuclear envelope disintegrates: The nuclear membrane dissolves, leaving an open area of cytoplasm in which a network of proteins (microtubules) has enough space to create pathways reaching from one side of the cell to the other – the spindle apparatus.
• Centrosomes move apart: The centrosomes move apart, and the spindle forms between them, and the spindle microtubules begin to capture chromosomes.
• Sister chromatids captured: The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles.

It is important to note that prophase II is different from prophase I, which is the first step of meiosis I.