Having an issue with a formula...

VLOOKUP(LOOKUP(9E+307,B:B),B:D,3,FALSE)

I want to find the last date in column B and then pull the date from column
D in the same row.

This works fine as long as there's no data in column C, but if there is, the
formula shows 0 instead of the data in column D.

Any idea why this is happening and how to fix it?

Thanks!