精液大量注入！5～オレの高飛車な美少女ご主人様がこんなに盛大にアヘるわけがない!?～

A young man (protagonist) working his way though school as a rich family's house butler was mistreated daily by his high-soaring mistress and her first maid. He was butler in name, but in actuality his status was a lowly slave. One day. A small package arrived in the mail, addressed to the housemaster (the bitchy mistress's grandfather). Some sort of medicine...?

The protagonist peeked inside and found a special drug that promised to increase one's sperm load to 1 litre, with aphrodisiac effects. Who knew such a thing existed... The next day. Amid his misery, he noticed a timid maid who watched his suffering without intervening at all. He was convinced that in her heart, she too looked down on him. And in a fit of rage, he drank the aphrodisiac.