Nodoka and Yue practicing casting spells. While training, Yue convince Nodoka that they casting a red string of fate spell on Nodoka. A spell which shows them whose their fate is. One end connect to Nodoka and the other end connect to Negi. Unfortunatly, this spell isn’t a fate connection, but it just connects two people with a red string. The rest is about how Nodoka and Negi spend the day trying to take their bath, while their hands are tie together.
On the English DVD of the Natsu(Summer) OVA (as well as the Spring OVA) In the Blurb on the back of the box the Class is mistakenly called class 2C - however it is possible that this is a typo